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DOE OSTI2020

Materials Data on HfCr2 by Materials Project

HfCr2 is Hexagonal Laves-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are five inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Cr atoms. All Hf–Hf bond lengths are 3.08 Å. There are three shorter (2.91 Å) and nine longer (2.95 Å) Hf–Cr bond lengths. In the second Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Cr atoms. All Hf–Hf bond lengths are 3.08 Å. There are three shorter (2.91 Å) and nine longer (2.95 Å) Hf–Cr bond lengths. In the third Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Cr atoms. There are one shorter (3.06 Å) and three longer (3.08 Å) Hf–Hf bond lengths. There are a spread of Hf–Cr bond distances ranging from 2.93–2.96 Å. In the fourth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Cr atoms. There are one shorter (3.06 Å) and three longer (3.08 Å) Hf–Hf bond lengths. There are a spread of Hf–Cr bond distances ranging from 2.93–2.96 Å. In the fifth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Cr atoms. There are a spread of Hf–Cr bond distances ranging from 2.93–2.96 Å. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded to six Hf and six Cr atoms to form a mixture of edge, face, and corner-sharing CrHf6Cr6 cuboctahedra. There are two shorter (2.48 Å) and four longer (2.52 Å) Cr–Cr bond lengths. In the second Cr site, Cr is bonded to six Hf and six Cr atoms to form a mixture of edge, face, and corner-sharing CrHf6Cr6 cuboctahedra. All Cr–Cr bond lengths are 2.54 Å. In the third Cr site, Cr is bonded to six Hf and six Cr atoms to form a mixture of edge, face, and corner-sharing CrHf6Cr6 cuboctahedra. There are two shorter (2.48 Å) and two longer (2.55 Å) Cr–Cr bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfMn2 by Materials Project

HfMn2 is Hexagonal Laves-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are five inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Mn atoms. There are one shorter (3.02 Å) and three longer (3.03 Å) Hf–Hf bond lengths. There are three shorter (2.89 Å) and nine longer (2.90 Å) Hf–Mn bond lengths. In the second Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Mn atoms. All Hf–Hf bond lengths are 3.03 Å. There are three shorter (2.89 Å) and nine longer (2.90 Å) Hf–Mn bond lengths. In the third Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Mn atoms. There are one shorter (3.02 Å) and three longer (3.03 Å) Hf–Hf bond lengths. There are three shorter (2.89 Å) and nine longer (2.90 Å) Hf–Mn bond lengths. In the fourth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Mn atoms. The Hf–Hf bond length is 3.04 Å. There are three shorter (2.89 Å) and nine longer (2.90 Å) Hf–Mn bond lengths. In the fifth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Mn atoms. There are three shorter (2.89 Å) and nine longer (2.90 Å) Hf–Mn bond lengths. There are three inequivalent Mn sites. In the first Mn site, Mn is bonded to six Hf and six Mn atoms to form a mixture of corner, edge, and face-sharing MnHf6Mn6 cuboctahedra. There are three shorter (2.47 Å) and three longer (2.49 Å) Mn–Mn bond lengths. In the second Mn site, Mn is bonded to six Hf and six Mn atoms to form a mixture of corner, edge, and face-sharing MnHf6Mn6 cuboctahedra. All Mn–Mn bond lengths are 2.47 Å. In the third Mn site, Mn is bonded to six Hf and six Mn atoms to form a mixture of corner, edge, and face-sharing MnHf6Mn6 cuboctahedra. There are two shorter (2.43 Å) and two longer (2.52 Å) Mn–Mn bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf3(CrGa2)2 by Materials Project

Hf3(CrGa2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are six inequivalent Hf sites. In the first Hf site, Hf is bonded in a 7-coordinate geometry to seven Ga atoms. There are a spread of Hf–Ga bond distances ranging from 2.71–3.02 Å. In the second Hf site, Hf is bonded in a 10-coordinate geometry to two equivalent Cr and eight Ga atoms. Both Hf–Cr bond lengths are 2.94 Å. There are a spread of Hf–Ga bond distances ranging from 2.92–3.12 Å. In the third Hf site, Hf is bonded in a 8-coordinate geometry to two equivalent Cr and eight Ga atoms. Both Hf–Cr bond lengths are 2.80 Å. There are a spread of Hf–Ga bond distances ranging from 2.76–3.25 Å. In the fourth Hf site, Hf is bonded in a 7-coordinate geometry to two equivalent Cr and seven Ga atoms. Both Hf–Cr bond lengths are 2.94 Å. There are a spread of Hf–Ga bond distances ranging from 2.73–2.93 Å. In the fifth Hf site, Hf is bonded in a 7-coordinate geometry to two equivalent Cr and seven Ga atoms. Both Hf–Cr bond lengths are 2.95 Å. There are a spread of Hf–Ga bond distances ranging from 2.83–2.94 Å. In the sixth Hf site, Hf is bonded in a 7-coordinate geometry to two equivalent Cr and seven Ga atoms. Both Hf–Cr bond lengths are 2.99 Å. There are a spread of Hf–Ga bond distances ranging from 2.74–2.88 Å. There are two inequivalent Cr sites. In the first Cr site, Cr is bonded in a 12-coordinate geometry to five Hf, two equivalent Cr, and five Ga atoms. There are one shorter (2.38 Å) and one longer (2.88 Å) Cr–Cr bond lengths. There are a spread of Cr–Ga bond distances ranging from 2.55–2.60 Å. In the second Cr site, Cr is bonded in a 7-coordinate geometry to one Cr and six Ga atoms. The Cr–Cr bond length is 2.47 Å. There are a spread of Cr–Ga bond distances ranging from 2.54–2.71 Å. There are seven inequivalent Ga sites. In the first Ga site, Ga is bonded in a 10-coordinate geometry to seven Hf and three Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.57–2.69 Å. In the second Ga site, Ga is bonded in a 11-coordinate geometry to six Hf, two equivalent Cr, and three Ga atoms. The Ga–Ga bond length is 2.62 Å. In the third Ga site, Ga is bonded in a 9-coordinate geometry to five Hf and four equivalent Cr atoms. In the fourth Ga site, Ga is bonded in a 9-coordinate geometry to five Hf and four Cr atoms. In the fifth Ga site, Ga is bonded in a 9-coordinate geometry to four Hf, four Cr, and one Ga atom. In the sixth Ga site, Ga is bonded in a 9-coordinate geometry to five Hf and four Cr atoms. In the seventh Ga site, Ga is bonded in a 9-coordinate geometry to five Hf and four Cr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Hf–N bond distances ranging from 2.09–2.20 Å. There are one shorter (2.20 Å) and one longer (2.28 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.11 Å. There are a spread of Hf–O bond distances ranging from 2.22–2.27 Å. In the third Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are one shorter (2.06 Å) and two longer (2.13 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.11–2.32 Å. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN5O octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.24 Å. There are one shorter (2.21 Å) and one longer (2.29 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Hf–N bond distances ranging from 2.13–2.23 Å. The Hf–O bond length is 2.23 Å. In the sixth Hf4+ site, Hf4+ is bonded to two N3- and four O2- atoms to form distorted HfN2O4 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 49–56°. There are one shorter (2.08 Å) and one longer (2.13 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.10–2.20 Å. In the seventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.20 Å. There are one shorter (2.24 Å) and one longer (2.30 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.20 Å. There are one shorter (2.16 Å) and one longer (2.17 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.16 Å. There are one shorter (2.20 Å) and one longer (2.36 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.09–2.21 Å. There are one shorter (2.26 Å) and one longer (2.28 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.10–2.25 Å. There are one shorter (2.19 Å) and one longer (2.22 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.22 Å. The Hf–O bond length is 2.26 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Hf–N bond distances ranging from 2.13–2.16 Å. There are a spread of Hf–O bond distances ranging from 2.11–2.21 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.15–2.27 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 53–60°. There are a spread of Hf–N bond distances ranging from 2.10–2.22 Å. The Hf–O bond length is 2.31 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–60°. There are a spread of Hf–N bond distances ranging from 2.11–2.23 Å. There are one shorter (2.19 Å) and one longer (2.30 Å) Hf–O bond lengths. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with f

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Hf–N bond distances ranging from 2.07–2.12 Å. There are a spread of Hf–O bond distances ranging from 2.17–2.28 Å. In the second Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.11–2.17 Å. There are one shorter (2.25 Å) and one longer (2.26 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are one shorter (2.08 Å) and two longer (2.13 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.11–2.32 Å. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Hf–N bond distances ranging from 2.12–2.25 Å. There are one shorter (2.13 Å) and one longer (2.24 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.19 Å. There are one shorter (2.22 Å) and one longer (2.27 Å) Hf–O bond lengths. In the sixth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Hf–N bond distances ranging from 2.08–2.16 Å. There are a spread of Hf–O bond distances ranging from 2.16–2.22 Å. In the seventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form HfN3O3 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.07–2.17 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.28 Å. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 50–57°. There are a spread of Hf–N bond distances ranging from 2.14–2.23 Å. There are one shorter (2.15 Å) and one longer (2.16 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.10–2.23 Å. The Hf–O bond length is 2.36 Å. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Hf–N bond distances ranging from 2.09–2.20 Å. There are one shorter (2.24 Å) and one longer (2.26 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.24 Å. There are one shorter (2.21 Å) and one longer (2.26 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted corner and edge-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.13–2.21 Å. The Hf–O bond length is 2.24 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are two shorter (2.14 Å) and one longer (2.15 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.11–2.20 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.14–2.26 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Hf–N bond distances ranging from 2.09–2.22 Å. The Hf–O bond length is 2.30 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. There are one shorter (2.19 Å) and one longer (2.30 Å) Hf–O bond lengths. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the third O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids,

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.19 Å. There are one shorter (2.21 Å) and one longer (2.24 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Hf–N bond distances ranging from 2.09–2.20 Å. There are one shorter (2.11 Å) and two longer (2.20 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.18 Å. There are one shorter (2.31 Å) and one longer (2.33 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.23 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.22 Å. In the fifth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.10–2.18 Å. There are one shorter (2.26 Å) and one longer (2.27 Å) Hf–O bond lengths. In the sixth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Hf–N bond distances ranging from 2.13–2.25 Å. There are one shorter (2.12 Å) and one longer (2.25 Å) Hf–O bond lengths. In the seventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–53°. There are a spread of Hf–N bond distances ranging from 2.11–2.22 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.18 Å. In the eighth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.15–2.27 Å. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.08–2.19 Å. There are one shorter (2.28 Å) and one longer (2.29 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Hf–N bond distances ranging from 2.07–2.20 Å. There are one shorter (2.26 Å) and one longer (2.29 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN3O3 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.21 Å. There are one shorter (2.23 Å) and one longer (2.26 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.13–2.25 Å. The Hf–O bond length is 2.24 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 49–58°. There are a spread of Hf–N bond distances ranging from 2.07–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.22 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. There are one shorter (2.20 Å) and one longer (2.23 Å) Hf–O bond lengths. In the fifteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Hf–N bond distances ranging from 2.14–2.22 Å. The Hf–O bond length is 2.22 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.20 Å. There are one shorter (2.17 Å) and one longer (2.19 Å) Hf–O bond lengths. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, and edges with four OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with four OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with four OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with four OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NH

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form HfN3O3 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 50–57°. There are a spread of Hf–N bond distances ranging from 2.07–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.27 Å. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are one shorter (2.07 Å) and two longer (2.16 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.16–2.24 Å. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN5O octahedra, edges with four HfN3O3 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.14 Å. There are one shorter (2.35 Å) and one longer (2.36 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with four HfN3O3 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 50–53°. There are one shorter (2.13 Å) and two longer (2.15 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.10–2.20 Å. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 48–59°. There are a spread of Hf–N bond distances ranging from 2.06–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.15–2.24 Å. In the sixth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra, edges with four HfN3O3 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 52–60°. There are a spread of Hf–N bond distances ranging from 2.10–2.23 Å. The Hf–O bond length is 2.39 Å. In the seventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with four HfN3O3 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Hf–N bond distances ranging from 2.13–2.22 Å. There are one shorter (2.13 Å) and one longer (2.20 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Hf–N bond distances ranging from 2.07–2.17 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.26 Å. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 51–60°. There are a spread of Hf–N bond distances ranging from 2.09–2.19 Å. There are one shorter (2.24 Å) and one longer (2.27 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Hf–N bond distances ranging from 2.16–2.19 Å. There are one shorter (2.15 Å) and one longer (2.18 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–61°. There are a spread of Hf–N bond distances ranging from 2.11–2.22 Å. There are one shorter (2.23 Å) and one longer (2.28 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Hf–N bond distances ranging from 2.10–2.23 Å. The Hf–O bond length is 2.33 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.20 Å. The Hf–O bond length is 2.28 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with four HfN4O2 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 54–56°. There are a spread of Hf–N bond distances ranging from 2.14–2.29 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN3O3 octahedra, edges with four HfN4O2 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 51–56°. There are one shorter (2.07 Å) and two longer (2.14 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.12–2.28 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Hf–N bond distances ranging from 2.13–2.21 Å. The Hf–O bond length is 2.23 Å. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with four NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ at

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN2O4 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.21 Å. There are one shorter (2.24 Å) and one longer (2.27 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 51–53°. There are one shorter (2.07 Å) and two longer (2.16 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.15–2.23 Å. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN5O octahedra, edges with four HfN4O2 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 54–56°. There are a spread of Hf–N bond distances ranging from 2.09–2.15 Å. There are one shorter (2.32 Å) and one longer (2.33 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded to two N3- and four O2- atoms to form distorted HfN2O4 octahedra that share corners with four HfN4O2 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 51–53°. There are one shorter (2.07 Å) and one longer (2.13 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.09–2.20 Å. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids that share corners with six HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 48–56°. There are a spread of Hf–N bond distances ranging from 2.07–2.17 Å. There are two shorter (2.15 Å) and one longer (2.22 Å) Hf–O bond lengths. In the sixth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra, edges with four HfN4O2 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.22 Å. The Hf–O bond length is 2.36 Å. In the seventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with four HfN4O2 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Hf–N bond distances ranging from 2.12–2.21 Å. There are one shorter (2.14 Å) and one longer (2.18 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with four HfN2O4 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Hf–N bond distances ranging from 2.10–2.20 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.20 Å. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN2O4 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.18 Å. There are one shorter (2.24 Å) and one longer (2.27 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form HfN3O3 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN2O4 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.11–2.16 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.22 Å. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with four HfN2O4 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 53–61°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. There are one shorter (2.22 Å) and one longer (2.29 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN2O4 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Hf–N bond distances ranging from 2.11–2.22 Å. The Hf–O bond length is 2.28 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. The Hf–O bond length is 2.28 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with four HfN4O2 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Hf–N bond distances ranging from 2.13–2.28 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with four HfN4O2 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.18 Å. There are one shorter (2.30 Å) and one longer (2.35 Å) Hf–O bond lengths. In the sixteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 54–56°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. The Hf–O bond length is 2.25 Å. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with seven NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with three NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with seven NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with three NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, and edges with three NHf4 tetrahedra. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with five NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, edges with two NHf4 tetrahedra, and an edgeedge with one NHf4 trigonal pyramid. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with five NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with five NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with seve

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form HfN3O3 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 51–59°. There are one shorter (2.08 Å) and two longer (2.12 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.19–2.24 Å. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 49–55°. There are a spread of Hf–N bond distances ranging from 2.07–2.17 Å. There are two shorter (2.15 Å) and one longer (2.22 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with four HfN3O3 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of Hf–N bond distances ranging from 2.09–2.16 Å. There are one shorter (2.32 Å) and one longer (2.37 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with four HfN3O3 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–52°. There are a spread of Hf–N bond distances ranging from 2.09–2.16 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.22 Å. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 48–56°. There are a spread of Hf–N bond distances ranging from 2.07–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.22 Å. In the sixth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of Hf–N bond distances ranging from 2.09–2.22 Å. There are two shorter (2.14 Å) and one longer (2.19 Å) Hf–O bond lengths. In the seventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.19 Å. There are one shorter (2.21 Å) and one longer (2.27 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with four HfN3O3 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–54°. There are a spread of Hf–N bond distances ranging from 2.11–2.19 Å. There are two shorter (2.14 Å) and one longer (2.17 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.21 Å. There are one shorter (2.22 Å) and one longer (2.26 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra, edges with four HfN3O3 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Hf–N bond distances ranging from 2.12–2.22 Å. The Hf–O bond length is 2.34 Å. In the eleventh Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. The Hf–O bond length is 2.28 Å. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. The Hf–O bond length is 2.31 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 54–56°. There are a spread of Hf–N bond distances ranging from 2.11–2.18 Å. There are one shorter (2.24 Å) and one longer (2.26 Å) Hf–O bond lengths. In the fourteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.17 Å. There are one shorter (2.29 Å) and one longer (2.33 Å) Hf–O bond lengths. In the fifteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. The Hf–O bond length is 2.22 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form a mixture of distorted edge and corner-sharing HfN6 octahedra. The corner-sharing octahedra tilt angles range from 55–56°. There are a spread of Hf–N bond distances ranging from 2.15–2.26 Å. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, and edges with four OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with seven NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with four NHf4 trigonal pyramids, and edges with four OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with seven NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with four NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with seven NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with three NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with seven NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with three NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, and edges with four NHf4 tetrahedra. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with seven NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with three NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with seven NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with four NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, and edges with four NHf4 tetrahedra. In the third O2- site, O2- is bonded to fo

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.13 Å. There are a spread of Hf–O bond distances ranging from 2.19–2.25 Å. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Hf–N bond distances ranging from 2.08–2.21 Å. There are one shorter (2.13 Å) and two longer (2.19 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN5O octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.18 Å. There are one shorter (2.29 Å) and one longer (2.33 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 50–53°. There are a spread of Hf–N bond distances ranging from 2.11–2.17 Å. There are two shorter (2.15 Å) and one longer (2.20 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted corner and edge-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Hf–N bond distances ranging from 2.08–2.19 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.20 Å. In the sixth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted corner and edge-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Hf–N bond distances ranging from 2.10–2.21 Å. There are two shorter (2.14 Å) and one longer (2.20 Å) Hf–O bond lengths. In the seventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.19 Å. There are one shorter (2.24 Å) and one longer (2.25 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of corner and edge-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 55–58°. There are a spread of Hf–N bond distances ranging from 2.15–2.20 Å. The Hf–O bond length is 2.24 Å. In the ninth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.23 Å. The Hf–O bond length is 2.39 Å. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.18 Å. There are one shorter (2.20 Å) and one longer (2.29 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.18 Å. There are one shorter (2.27 Å) and one longer (2.28 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–53°. There are a spread of Hf–N bond distances ranging from 2.10–2.19 Å. There are one shorter (2.17 Å) and one longer (2.23 Å) Hf–O bond lengths. In the thirteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.18 Å. Both Hf–O bond lengths are 2.25 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.21 Å. There are one shorter (2.22 Å) and one longer (2.28 Å) Hf–O bond lengths. In the fifteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted corner and edge-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Hf–N bond distances ranging from 2.13–2.23 Å. The Hf–O bond length is 2.22 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form a mixture of distorted corner and edge-sharing HfN6 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.15–2.27 Å. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, and edges with four OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with four OHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with four OHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with five NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with four NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with four OHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, edges with three NHf4 tetrahedra, and an edgeedge with one NHf4 trigonal pyramid. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with five NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the third O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the fourth O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the fifth O2-

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Hf–N bond distances ranging from 2.10–2.19 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.21 Å. In the second Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of corner and edge-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.24 Å. The Hf–O bond length is 2.26 Å. In the third Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN5O octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–56°. There are two shorter (2.08 Å) and one longer (2.13 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.16–2.30 Å. In the fourth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN5O octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.09–2.22 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.21 Å. In the fifth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted corner and edge-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.10–2.20 Å. The Hf–O bond length is 2.28 Å. In the sixth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted corner and edge-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Hf–N bond distances ranging from 2.07–2.14 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.32 Å. In the seventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of corner and edge-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.07–2.10 Å. There are two shorter (2.25 Å) and one longer (2.28 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.07–2.20 Å. There are one shorter (2.26 Å) and one longer (2.30 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN5O octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.14–2.29 Å. The Hf–O bond length is 2.21 Å. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.18 Å. There are one shorter (2.22 Å) and one longer (2.27 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with five HfN5O octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Hf–N bond distances ranging from 2.12–2.22 Å. There are one shorter (2.16 Å) and one longer (2.17 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN5O octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. The Hf–O bond length is 2.27 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids that share corners with six HfN3O3 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 49–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.19 Å. There are a spread of Hf–O bond distances ranging from 2.15–2.20 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.12–2.21 Å. There are one shorter (2.21 Å) and one longer (2.23 Å) Hf–O bond lengths. In the fifteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.15–2.25 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN3O3 octahedra, edges with five HfN5O octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.14–2.22 Å. There are one shorter (2.16 Å) and one longer (2.20 Å) Hf–O bond lengths. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with three NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, edges with two NHf4 tetrahedra, and an edgeedge with one NHf4 trigonal pyramid. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with three NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to two N3- and four O2- atoms to form HfN2O4 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. There are one shorter (2.06 Å) and one longer (2.10 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.11–2.24 Å. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids that share corners with six HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. There are a spread of Hf–N bond distances ranging from 2.07–2.17 Å. There are two shorter (2.16 Å) and one longer (2.23 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with five HfN2O4 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 49–53°. There are a spread of Hf–N bond distances ranging from 2.16–2.19 Å. Both Hf–O bond lengths are 2.15 Å. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN5O octahedra, edges with five HfN2O4 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.16 Å. There are one shorter (2.36 Å) and one longer (2.39 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 49–59°. There are a spread of Hf–N bond distances ranging from 2.06–2.20 Å. There are two shorter (2.15 Å) and one longer (2.25 Å) Hf–O bond lengths. In the sixth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra, edges with five HfN2O4 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–60°. There are a spread of Hf–N bond distances ranging from 2.11–2.23 Å. The Hf–O bond length is 2.37 Å. In the seventh Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN2O4 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Hf–N bond distances ranging from 2.13–2.24 Å. The Hf–O bond length is 2.30 Å. In the eighth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with six HfN4O2 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.22 Å. The Hf–O bond length is 2.33 Å. In the ninth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There are a spread of Hf–N bond distances ranging from 2.09–2.24 Å. The Hf–O bond length is 2.30 Å. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 51–60°. There are a spread of Hf–N bond distances ranging from 2.08–2.20 Å. There are one shorter (2.21 Å) and one longer (2.27 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 49–55°. There are a spread of Hf–N bond distances ranging from 2.07–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.29 Å. In the twelfth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with five HfN2O4 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.20 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.19 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.16 Å. There are one shorter (2.25 Å) and one longer (2.27 Å) Hf–O bond lengths. In the fourteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN2O4 octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–57°. There are one shorter (2.08 Å) and two longer (2.15 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.14–2.27 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 50–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. The Hf–O bond length is 2.23 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.16–2.24 Å. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with five NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyrami

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.06–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.15–2.28 Å. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Hf–N bond distances ranging from 2.12–2.16 Å. There are a spread of Hf–O bond distances ranging from 2.11–2.24 Å. In the third Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN5O octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.06–2.10 Å. There are a spread of Hf–O bond distances ranging from 2.17–2.33 Å. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Hf–N bond distances ranging from 2.13–2.22 Å. There are one shorter (2.15 Å) and one longer (2.19 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 47–59°. There are one shorter (2.06 Å) and two longer (2.18 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.15–2.25 Å. In the sixth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Hf–N bond distances ranging from 2.09–2.22 Å. The Hf–O bond length is 2.37 Å. In the seventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Hf–N bond distances ranging from 2.07–2.17 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.25 Å. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN3O3 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.15–2.19 Å. There are one shorter (2.13 Å) and one longer (2.19 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of Hf–N bond distances ranging from 2.07–2.19 Å. There are one shorter (2.28 Å) and one longer (2.29 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.22 Å. There are one shorter (2.13 Å) and one longer (2.21 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Hf–N bond distances ranging from 2.14–2.20 Å. There are one shorter (2.15 Å) and one longer (2.23 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 51–61°. There are a spread of Hf–N bond distances ranging from 2.11–2.25 Å. The Hf–O bond length is 2.25 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 50–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.21 Å. The Hf–O bond length is 2.28 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form a mixture of distorted edge and corner-sharing HfN6 octahedra. The corner-sharing octahedra tilt angles range from 50–57°. There are a spread of Hf–N bond distances ranging from 2.14–2.28 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Hf–N bond distances ranging from 2.06–2.15 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.30 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Hf–N bond distances ranging from 2.14–2.20 Å. The Hf–O bond length is 2.21 Å. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahed

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 51–54°. There are a spread of Hf–N bond distances ranging from 2.12–2.21 Å. There are one shorter (2.13 Å) and one longer (2.21 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of corner and edge-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.11–2.24 Å. The Hf–O bond length is 2.28 Å. In the third Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN5O octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.08–2.21 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.22 Å. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN5O octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.08–2.21 Å. There are one shorter (2.18 Å) and one longer (2.30 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to two N3- and four O2- atoms to form distorted HfN2O4 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are one shorter (2.07 Å) and one longer (2.08 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.12–2.26 Å. In the sixth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Hf–N bond distances ranging from 2.10–2.21 Å. The Hf–O bond length is 2.28 Å. In the seventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form HfN3O3 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.07–2.10 Å. There are one shorter (2.24 Å) and two longer (2.26 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN5O octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.08–2.17 Å. There are one shorter (2.20 Å) and one longer (2.36 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN5O octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. There are one shorter (2.15 Å) and one longer (2.17 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.18 Å. There are one shorter (2.26 Å) and one longer (2.28 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.09–2.17 Å. There are one shorter (2.22 Å) and one longer (2.29 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN5O octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.24 Å. The Hf–O bond length is 2.25 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.27 Å. There are one shorter (2.21 Å) and one longer (2.22 Å) Hf–O bond lengths. In the fourteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.16–2.27 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Hf–N bond distances ranging from 2.09–2.16 Å. There are a spread of Hf–O bond distances ranging from 2.15–2.23 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 50–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. There are one shorter (2.17 Å) and one longer (2.23 Å) Hf–O bond lengths. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the second O2- site, O2- is bonded to four Hf4+ atoms to form OHf4 trigonal pyramids

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN3O3 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.21 Å. There are one shorter (2.24 Å) and one longer (2.29 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 50–53°. There are a spread of Hf–N bond distances ranging from 2.13–2.15 Å. There are a spread of Hf–O bond distances ranging from 2.09–2.24 Å. In the third Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Hf–N bond distances ranging from 2.10–2.20 Å. There are one shorter (2.12 Å) and two longer (2.19 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.15 Å. There are one shorter (2.32 Å) and one longer (2.35 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 49–56°. There are a spread of Hf–N bond distances ranging from 2.09–2.19 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.19 Å. In the sixth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–61°. There are a spread of Hf–N bond distances ranging from 2.10–2.23 Å. There are one shorter (2.22 Å) and one longer (2.25 Å) Hf–O bond lengths. In the seventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of Hf–N bond distances ranging from 2.10–2.21 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.21 Å. In the eighth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.20 Å. The Hf–O bond length is 2.31 Å. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Hf–N bond distances ranging from 2.08–2.19 Å. There are one shorter (2.30 Å) and one longer (2.31 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Hf–N bond distances ranging from 2.13–2.20 Å. There are one shorter (2.14 Å) and one longer (2.19 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are one shorter (2.11 Å) and two longer (2.15 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.14–2.22 Å. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra, edges with five HfN4O2 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. The Hf–O bond length is 2.33 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. The Hf–O bond length is 2.28 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.07–2.12 Å. There are a spread of Hf–O bond distances ranging from 2.16–2.32 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.13–2.28 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.11–2.24 Å. The Hf–O bond length is 2.24 Å. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, a cornercorner with one OHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with three NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 tetrahedra, edges with two NHf4 tetrahedra, and an edgeedge with one NHf4 trigonal pyramid. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one OHf4 tetrahedra, corners with four NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyram

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.08–2.22 Å. There are one shorter (2.23 Å) and one longer (2.29 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to two N3- and four O2- atoms to form a mixture of distorted edge and corner-sharing HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are one shorter (2.07 Å) and one longer (2.14 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.09–2.21 Å. In the third Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. There are a spread of Hf–N bond distances ranging from 2.10–2.16 Å. There are a spread of Hf–O bond distances ranging from 2.15–2.21 Å. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 55–57°. There are a spread of Hf–N bond distances ranging from 2.08–2.15 Å. There are one shorter (2.32 Å) and one longer (2.36 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 49–56°. There are one shorter (2.08 Å) and two longer (2.18 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.13–2.19 Å. In the sixth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–53°. There are a spread of Hf–N bond distances ranging from 2.09–2.21 Å. There are a spread of Hf–O bond distances ranging from 2.14–2.20 Å. In the seventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 50–60°. There are a spread of Hf–N bond distances ranging from 2.09–2.21 Å. There are one shorter (2.26 Å) and one longer (2.27 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–60°. There are a spread of Hf–N bond distances ranging from 2.09–2.18 Å. There are one shorter (2.21 Å) and one longer (2.28 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 54–60°. There are a spread of Hf–N bond distances ranging from 2.12–2.24 Å. The Hf–O bond length is 2.37 Å. In the tenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 54–60°. There are a spread of Hf–N bond distances ranging from 2.09–2.18 Å. There are one shorter (2.28 Å) and one longer (2.32 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of Hf–N bond distances ranging from 2.12–2.22 Å. Both Hf–O bond lengths are 2.16 Å. In the twelfth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 53–60°. There are one shorter (2.09 Å) and three longer (2.16 Å) Hf–N bond lengths. There are one shorter (2.21 Å) and one longer (2.32 Å) Hf–O bond lengths. In the thirteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Hf–N bond distances ranging from 2.11–2.19 Å. The Hf–O bond length is 2.27 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.16–2.27 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Hf–N bond distances ranging from 2.07–2.12 Å. There are a spread of Hf–O bond distances ranging from 2.19–2.29 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to six N3- atoms to form distorted HfN6 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 54–56°. There are a spread of Hf–N bond distances ranging from 2.14–2.24 Å. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with six NHf4 tetrahedra, corners with three NHf4 trigonal pyramids, corners with three OHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with seven NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with four NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with four NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with six NHf4 tetrahedra, corners with three NHf4 trigonal pyramids, corners with three OHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with six NHf4 tetrahedra, corners with three NHf4 trigonal pyramids, corners with three OHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with six NHf4 tetrahedra, corners with three NHf4 trigonal pyramids, corners with three OHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with six NHf4 tetrahedra, corners with three NHf4 trigonal pyramids, corners with three OHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, and edges with four NHf4 tetrahedra. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with six NHf4 tetrahedra, corners with three NHf4 trigonal pyramids, corners with three OHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with seven NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with four NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and an edgeedge with one OHf4 trigonal pyramid. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, edges with three NHf4 tetrahedra, and an edgeedge with one NHf4 trigonal pyramid. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, edges with two NHf4 tetrahedra, and edges with two NHf4 trigonal pyramids. In the third O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with five OHf4 trigonal pyramids, edges with three NHf4 tetrahedra, and an edgeedge with one OHf4 trigonal pyramid. In the fourth O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with seven NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with four NHf4 trigonal pyramids, an edgeedge with o

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf7P4 by Materials Project

Hf7P4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are eight inequivalent Hf sites. In the first Hf site, Hf is bonded in a 5-coordinate geometry to five P atoms. There are four shorter (2.68 Å) and one longer (3.10 Å) Hf–P bond lengths. In the second Hf site, Hf is bonded to five P atoms to form a mixture of distorted edge, face, and corner-sharing HfP5 trigonal bipyramids. There are one shorter (2.62 Å) and four longer (2.68 Å) Hf–P bond lengths. In the third Hf site, Hf is bonded in a 5-coordinate geometry to five P atoms. There are a spread of Hf–P bond distances ranging from 2.69–3.04 Å. In the fourth Hf site, Hf is bonded to five P atoms to form a mixture of distorted edge, face, and corner-sharing HfP5 trigonal bipyramids. There are a spread of Hf–P bond distances ranging from 2.57–2.71 Å. In the fifth Hf site, Hf is bonded in a 4-coordinate geometry to four P atoms. There are a spread of Hf–P bond distances ranging from 2.61–2.87 Å. In the sixth Hf site, Hf is bonded in a 4-coordinate geometry to five P atoms. There are a spread of Hf–P bond distances ranging from 2.69–3.29 Å. In the seventh Hf site, Hf is bonded in a square co-planar geometry to four P atoms. There are two shorter (2.71 Å) and two longer (2.73 Å) Hf–P bond lengths. In the eighth Hf site, Hf is bonded in a distorted square co-planar geometry to four P atoms. There are two shorter (2.60 Å) and two longer (2.85 Å) Hf–P bond lengths. There are four inequivalent P sites. In the first P site, P is bonded in a 7-coordinate geometry to nine Hf atoms. In the second P site, P is bonded in a 9-coordinate geometry to nine Hf atoms. In the third P site, P is bonded to seven Hf atoms to form a mixture of distorted edge and corner-sharing PHf7 pentagonal bipyramids. In the fourth P site, P is bonded in a 8-coordinate geometry to eight Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf14Cu51 by Materials Project

Cu51Hf14 is Bergman Structure: Mg32(Al,Zn)49 Bergman-derived structured and crystallizes in the hexagonal P-6 space group. The structure is three-dimensional. there are five inequivalent Hf sites. In the first Hf site, Hf is bonded in a 6-coordinate geometry to fifteen Cu atoms. There are a spread of Hf–Cu bond distances ranging from 2.68–2.94 Å. In the second Hf site, Hf is bonded in a 12-coordinate geometry to fourteen Cu atoms. There are a spread of Hf–Cu bond distances ranging from 2.78–2.88 Å. In the third Hf site, Hf is bonded in a 12-coordinate geometry to fourteen Cu atoms. There are a spread of Hf–Cu bond distances ranging from 2.67–2.97 Å. In the fourth Hf site, Hf is bonded in a 12-coordinate geometry to fourteen Cu atoms. There are a spread of Hf–Cu bond distances ranging from 2.72–3.02 Å. In the fifth Hf site, Hf is bonded in a 8-coordinate geometry to fourteen Cu atoms. There are a spread of Hf–Cu bond distances ranging from 2.73–2.92 Å. There are thirteen inequivalent Cu sites. In the first Cu site, Cu is bonded in a 11-coordinate geometry to three equivalent Hf and eight Cu atoms. There are two shorter (2.44 Å) and six longer (2.55 Å) Cu–Cu bond lengths. In the second Cu site, Cu is bonded in a 11-coordinate geometry to three equivalent Hf and eight Cu atoms. There are two shorter (2.44 Å) and six longer (2.54 Å) Cu–Cu bond lengths. In the third Cu site, Cu is bonded in a 11-coordinate geometry to four Hf and seven Cu atoms. There are a spread of Cu–Cu bond distances ranging from 2.45–2.82 Å. In the fourth Cu site, Cu is bonded in a 11-coordinate geometry to four Hf and seven Cu atoms. There are a spread of Cu–Cu bond distances ranging from 2.46–2.81 Å. In the fifth Cu site, Cu is bonded to four Hf and eight Cu atoms to form a mixture of face, edge, and corner-sharing CuHf4Cu8 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.39–2.56 Å. In the sixth Cu site, Cu is bonded in a 10-coordinate geometry to three equivalent Hf and seven Cu atoms. All Cu–Cu bond lengths are 2.52 Å. In the seventh Cu site, Cu is bonded in a 10-coordinate geometry to three equivalent Hf and seven Cu atoms. All Cu–Cu bond lengths are 2.50 Å. In the eighth Cu site, Cu is bonded to four Hf and eight Cu atoms to form a mixture of face, edge, and corner-sharing CuHf4Cu8 cuboctahedra. There are two shorter (2.49 Å) and two longer (2.59 Å) Cu–Cu bond lengths. In the ninth Cu site, Cu is bonded in a 11-coordinate geometry to four Hf and seven Cu atoms. There are a spread of Cu–Cu bond distances ranging from 2.47–2.63 Å. In the tenth Cu site, Cu is bonded to four Hf and eight Cu atoms to form a mixture of distorted face, edge, and corner-sharing CuHf4Cu8 cuboctahedra. There are a spread of Cu–Cu bond distances ranging from 2.44–2.65 Å. In the eleventh Cu site, Cu is bonded in a 11-coordinate geometry to four Hf and seven Cu atoms. The Cu–Cu bond length is 2.52 Å. In the twelfth Cu site, Cu is bonded in a 12-coordinate geometry to four Hf and eight Cu atoms. The Cu–Cu bond length is 2.80 Å. In the thirteenth Cu site, Cu is bonded in a 2-coordinate geometry to four Hf and six Cu atoms. Both Cu–Cu bond lengths are 2.41 Å.

36 MATERIALS SCIENCE↗