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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↗
DOE OSTI2020

Materials Data on Hf2Be17 by Materials Project

Be17Hf2 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are ten inequivalent Be sites. In the first Be site, Be is bonded in a 2-coordinate geometry to thirteen Be and one Hf atom. There are a spread of Be–Be bond distances ranging from 2.11–2.40 Å. The Be–Hf bond length is 2.63 Å. In the second Be site, Be is bonded to ten Be and two Hf atoms to form a mixture of distorted corner, edge, and face-sharing BeHf2Be10 cuboctahedra. There are a spread of Be–Be bond distances ranging from 2.14–2.34 Å. There are one shorter (2.67 Å) and one longer (2.68 Å) Be–Hf bond lengths. In the third Be site, Be is bonded to nine Be and three Hf atoms to form a mixture of distorted corner, edge, and face-sharing BeHf3Be9 cuboctahedra. There are a spread of Be–Be bond distances ranging from 2.15–2.34 Å. There are a spread of Be–Hf bond distances ranging from 2.72–2.87 Å. In the fourth Be site, Be is bonded to nine Be and three Hf atoms to form a mixture of corner, edge, and face-sharing BeHf3Be9 cuboctahedra. There are a spread of Be–Be bond distances ranging from 2.15–2.34 Å. There are a spread of Be–Hf bond distances ranging from 2.71–2.83 Å. In the fifth Be site, Be is bonded to ten Be and two equivalent Hf atoms to form a mixture of distorted corner, edge, and face-sharing BeHf2Be10 cuboctahedra. There are four shorter (2.13 Å) and two longer (2.29 Å) Be–Be bond lengths. Both Be–Hf bond lengths are 2.85 Å. In the sixth Be site, Be is bonded in a 2-coordinate geometry to thirteen Be and one Hf atom. There are one shorter (2.10 Å) and six longer (2.40 Å) Be–Be bond lengths. The Be–Hf bond length is 2.63 Å. In the seventh Be site, Be is bonded to ten Be and two Hf atoms to form a mixture of distorted corner, edge, and face-sharing BeHf2Be10 cuboctahedra. There are a spread of Be–Be bond distances ranging from 2.13–2.29 Å. There are one shorter (2.82 Å) and one longer (2.85 Å) Be–Hf bond lengths. In the eighth Be site, Be is bonded to nine Be and three Hf atoms to form a mixture of distorted corner, edge, and face-sharing BeHf3Be9 cuboctahedra. There are two shorter (2.22 Å) and one longer (2.35 Å) Be–Be bond lengths. There are a spread of Be–Hf bond distances ranging from 2.74–2.83 Å. In the ninth Be site, Be is bonded in a 2-coordinate geometry to thirteen Be and one Hf atom. All Be–Be bond lengths are 2.40 Å. The Be–Hf bond length is 2.58 Å. In the tenth Be site, Be is bonded to ten Be and two Hf atoms to form a mixture of distorted corner, edge, and face-sharing BeHf2Be10 cuboctahedra. Both Be–Be bond lengths are 2.16 Å. Both Be–Hf bond lengths are 2.68 Å. There are four inequivalent Hf sites. In the first Hf site, Hf is bonded in a 1-coordinate geometry to nineteen Be atoms. In the second Hf site, Hf is bonded in a 8-coordinate geometry to twenty Be atoms. In the third Hf site, Hf is bonded in a 10-coordinate geometry to nineteen Be atoms. In the fourth Hf site, Hf is bonded in a 12-coordinate geometry to eighteen Be atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf5N5O2 by Materials Project

Hf5N5O2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are five inequivalent Hf sites. In the first Hf site, Hf is bonded to five N and one O atom to form a mixture of edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 2–59°. There are a spread of Hf–N bond distances ranging from 2.16–2.22 Å. The Hf–O bond length is 2.18 Å. In the second Hf site, Hf is bonded in a 7-coordinate geometry to five N and two equivalent O atoms. There are a spread of Hf–N bond distances ranging from 2.26–2.41 Å. Both Hf–O bond lengths are 2.22 Å. In the third Hf site, Hf is bonded in a 7-coordinate geometry to five N and two equivalent O atoms. There are a spread of Hf–N bond distances ranging from 2.25–2.38 Å. Both Hf–O bond lengths are 2.23 Å. In the fourth Hf site, Hf is bonded to five N and one O atom to form a mixture of edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 2–59°. There are a spread of Hf–N bond distances ranging from 2.16–2.22 Å. The Hf–O bond length is 2.16 Å. In the fifth Hf site, Hf is bonded to four N and two O atoms to form HfN4O2 octahedra that share corners with two HfN5O octahedra and edges with two equivalent HfN4O2 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two shorter (2.19 Å) and two longer (2.20 Å) Hf–N bond lengths. There are one shorter (2.11 Å) and one longer (2.12 Å) Hf–O bond lengths. There are five inequivalent N sites. In the first N site, N is bonded in a square co-planar geometry to four Hf atoms. In the second N site, N is bonded to five Hf atoms to form distorted NHf5 square pyramids that share corners with four equivalent OHf4 tetrahedra, corners with six NHf5 trigonal bipyramids, edges with two equivalent NHf5 square pyramids, edges with three OHf4 tetrahedra, and edges with four NHf5 trigonal bipyramids. In the third N site, N is bonded to five Hf atoms to form NHf5 trigonal bipyramids that share corners with two equivalent NHf5 square pyramids, corners with five OHf4 tetrahedra, corners with two equivalent NHf5 trigonal bipyramids, an edgeedge with one NHf5 square pyramid, an edgeedge with one OHf4 tetrahedra, and edges with four NHf5 trigonal bipyramids. In the fourth N site, N is bonded to five Hf atoms to form NHf5 trigonal bipyramids that share corners with two equivalent NHf5 square pyramids, corners with five OHf4 tetrahedra, corners with two equivalent NHf5 trigonal bipyramids, an edgeedge with one OHf4 tetrahedra, and edges with five NHf5 trigonal bipyramids. In the fifth N site, N is bonded to five Hf atoms to form distorted NHf5 trigonal bipyramids that share corners with two equivalent NHf5 square pyramids, corners with four equivalent OHf4 tetrahedra, corners with four NHf5 trigonal bipyramids, edges with three equivalent NHf5 square pyramids, edges with three OHf4 tetrahedra, and edges with three NHf5 trigonal bipyramids. There are two inequivalent O sites. In the first O site, O is bonded to four Hf atoms to form OHf4 tetrahedra that share corners with three OHf4 tetrahedra, corners with nine NHf5 trigonal bipyramids, edges with two equivalent NHf5 square pyramids, and edges with two NHf5 trigonal bipyramids. In the second O site, O is bonded to four Hf atoms to form OHf4 tetrahedra that share corners with four equivalent NHf5 square pyramids, corners with three OHf4 tetrahedra, corners with five NHf5 trigonal bipyramids, an edgeedge with one NHf5 square pyramid, and edges with three NHf5 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf5N5O2 by Materials Project

Hf5N5O2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are five inequivalent Hf sites. In the first Hf site, Hf is bonded to six N atoms to form HfN6 octahedra that share corners with three HfN5O octahedra and edges with five HfN6 octahedra. The corner-sharing octahedra tilt angles range from 7–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.30 Å. In the second Hf site, Hf is bonded in a 7-coordinate geometry to five N and three O atoms. There are four shorter (2.28 Å) and one longer (2.81 Å) Hf–N bond lengths. There are two shorter (2.20 Å) and one longer (2.48 Å) Hf–O bond lengths. In the third Hf site, Hf is bonded in a 7-coordinate geometry to five N and two equivalent O atoms. There are a spread of Hf–N bond distances ranging from 2.15–2.45 Å. Both Hf–O bond lengths are 2.36 Å. In the fourth Hf site, Hf is bonded to five N and one O atom to form a mixture of corner and edge-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 7–61°. There are a spread of Hf–N bond distances ranging from 2.17–2.21 Å. The Hf–O bond length is 2.18 Å. In the fifth Hf site, Hf is bonded to three N and three O atoms to form HfN3O3 octahedra that share corners with two HfN6 octahedra and edges with two equivalent HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There are one shorter (2.05 Å) and two longer (2.15 Å) Hf–N bond lengths. There are one shorter (2.17 Å) and two longer (2.25 Å) Hf–O bond lengths. There are five inequivalent N sites. In the first N site, N is bonded in a distorted rectangular see-saw-like geometry to five Hf atoms. In the second N site, N is bonded to five Hf atoms to form NHf5 trigonal bipyramids that share a cornercorner with one OHf4 tetrahedra, corners with four equivalent NHf4 tetrahedra, corners with two equivalent NHf5 trigonal bipyramids, corners with two equivalent OHf5 trigonal bipyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf5 trigonal bipyramid, and edges with four NHf5 trigonal bipyramids. In the third N site, N is bonded to five Hf atoms to form NHf5 trigonal bipyramids that share a cornercorner with one NHf4 tetrahedra, corners with four equivalent OHf4 tetrahedra, corners with two equivalent NHf5 trigonal bipyramids, corners with two equivalent OHf5 trigonal bipyramids, an edgeedge with one OHf4 tetrahedra, and edges with five NHf5 trigonal bipyramids. In the fourth N site, N is bonded to five Hf atoms to form distorted NHf5 trigonal bipyramids that share corners with four equivalent OHf4 tetrahedra, corners with two equivalent OHf5 trigonal bipyramids, corners with four NHf5 trigonal bipyramids, an edgeedge with one OHf4 tetrahedra, edges with two equivalent NHf4 tetrahedra, edges with three NHf5 trigonal bipyramids, and edges with three equivalent OHf5 trigonal bipyramids. In the fifth N site, N is bonded to four Hf atoms to form NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with two equivalent NHf4 tetrahedra, corners with four equivalent OHf5 trigonal bipyramids, corners with five NHf5 trigonal bipyramids, an edgeedge with one OHf5 trigonal bipyramid, and edges with three NHf5 trigonal bipyramids. There are two inequivalent O sites. In the first O site, O is bonded to four Hf atoms to form OHf4 tetrahedra that share a cornercorner with one NHf4 tetrahedra, corners with two equivalent OHf4 tetrahedra, corners with nine NHf5 trigonal bipyramids, edges with two NHf5 trigonal bipyramids, and edges with two equivalent OHf5 trigonal bipyramids. In the second O site, O is bonded to five Hf atoms to form distorted OHf5 trigonal bipyramids that share corners with four equivalent NHf4 tetrahedra, corners with six NHf5 trigonal bipyramids, an edgeedge with one NHf4 tetrahedra, edges with two equivalent OHf4 tetrahedra, edges with two equivalent OHf5 trigonal bipyramids, and edges with four NHf5 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaHf8(NCl)8 by Materials Project

NaHf8(NCl)8 crystallizes in the monoclinic P2/m space group. The structure is two-dimensional and consists of one NaHf8(NCl)8 sheet oriented in the (0, 0, 1) direction. Na is bonded to six Cl atoms to form edge-sharing NaCl6 octahedra. There are four shorter (2.75 Å) and two longer (2.77 Å) Na–Cl bond lengths. There are four inequivalent Hf sites. In the first Hf site, Hf is bonded in a 7-coordinate geometry to four N and three Cl atoms. There are three shorter (2.13 Å) and one longer (2.19 Å) Hf–N bond lengths. There are one shorter (2.75 Å) and two longer (2.77 Å) Hf–Cl bond lengths. In the second Hf site, Hf is bonded in a 7-coordinate geometry to four N and three Cl atoms. There are three shorter (2.13 Å) and one longer (2.19 Å) Hf–N bond lengths. There are one shorter (2.75 Å) and two longer (2.78 Å) Hf–Cl bond lengths. In the third Hf site, Hf is bonded in a 4-coordinate geometry to four N and three Cl atoms. There are one shorter (2.10 Å) and three longer (2.11 Å) Hf–N bond lengths. There are one shorter (2.85 Å) and two longer (2.92 Å) Hf–Cl bond lengths. In the fourth Hf site, Hf is bonded in a 4-coordinate geometry to four N and three Cl atoms. There are one shorter (2.11 Å) and three longer (2.12 Å) Hf–N bond lengths. There are two shorter (2.87 Å) and one longer (2.88 Å) Hf–Cl bond lengths. There are four inequivalent N sites. In the first N site, N is bonded to four Hf atoms to form NHf4 trigonal pyramids that share corners with three equivalent ClNa2Hf3 square pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one ClNa2Hf3 square pyramid, and edges with three NHf4 tetrahedra. In the second N site, N is bonded to four Hf atoms to form NHf4 trigonal pyramids that share corners with six NHf4 trigonal pyramids, edges with two equivalent ClNa2Hf3 square pyramids, and edges with three NHf4 tetrahedra. In the third N site, N is bonded to four Hf atoms to form NHf4 tetrahedra that share corners with two equivalent ClNa2Hf3 square pyramids, corners with six NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the fourth N site, N is bonded to four Hf atoms to form NHf4 tetrahedra that share a cornercorner with one ClNa2Hf3 square pyramid, corners with six NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. There are four inequivalent Cl sites. In the first Cl site, Cl is bonded to two equivalent Na and three Hf atoms to form distorted ClNa2Hf3 square pyramids that share corners with two equivalent ClNa2Hf3 square pyramids, corners with three NHf4 tetrahedra, corners with three equivalent NHf4 trigonal pyramids, edges with three equivalent ClNa2Hf3 square pyramids, and edges with three NHf4 trigonal pyramids. In the second Cl site, Cl is bonded in a distorted see-saw-like geometry to one Na and three Hf atoms. In the third Cl site, Cl is bonded in a 3-coordinate geometry to three Hf atoms. In the fourth Cl site, Cl is bonded in a 3-coordinate geometry to three Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf21Re25 by Materials Project

Hf21Re25 is Frank-Kasper $\mu$ Phase-like structured and crystallizes in the trigonal R-3c space group. The structure is three-dimensional. there are four inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four Re atoms. There are two shorter (2.88 Å) and two longer (2.94 Å) Hf–Re bond lengths. In the second Hf site, Hf is bonded in a 7-coordinate geometry to one Hf and seven Re atoms. The Hf–Hf bond length is 3.10 Å. There are a spread of Hf–Re bond distances ranging from 2.90–3.07 Å. In the third Hf site, Hf is bonded in a 12-coordinate geometry to four Hf and twelve Re atoms. There are two shorter (3.19 Å) and one longer (3.22 Å) Hf–Hf bond lengths. There are a spread of Hf–Re bond distances ranging from 3.03–3.19 Å. In the fourth Hf site, Hf is bonded in a 7-coordinate geometry to eight Re atoms. There are a spread of Hf–Re bond distances ranging from 2.93–3.27 Å. There are six inequivalent Re sites. In the first Re site, Re is bonded to six equivalent Hf and six Re atoms to form ReHf6Re6 cuboctahedra that share corners with sixteen ReHf6Re6 cuboctahedra, edges with six ReHf7Re5 cuboctahedra, and faces with eighteen ReHf6Re6 cuboctahedra. There are a spread of Re–Re bond distances ranging from 2.61–2.74 Å. In the second Re site, Re is bonded to seven Hf and five Re atoms to form a mixture of face, edge, and corner-sharing ReHf7Re5 cuboctahedra. There are a spread of Re–Re bond distances ranging from 2.65–2.70 Å. In the third Re site, Re is bonded to eight Hf and four Re atoms to form ReHf8Re4 cuboctahedra that share corners with eight ReHf7Re5 cuboctahedra, edges with two equivalent ReHf8Re4 cuboctahedra, and faces with fourteen ReHf7Re5 cuboctahedra. Both Re–Re bond lengths are 2.67 Å. In the fourth Re site, Re is bonded to seven Hf and five Re atoms to form ReHf7Re5 cuboctahedra that share corners with thirteen ReHf6Re6 cuboctahedra, edges with five ReHf7Re5 cuboctahedra, and faces with seventeen ReHf6Re6 cuboctahedra. There are one shorter (2.60 Å) and one longer (2.63 Å) Re–Re bond lengths. In the fifth Re site, Re is bonded to seven Hf and five Re atoms to form a mixture of distorted face, edge, and corner-sharing ReHf7Re5 cuboctahedra. The Re–Re bond length is 2.60 Å. In the sixth Re site, Re is bonded to six equivalent Hf and six equivalent Re atoms to form ReHf6Re6 cuboctahedra that share corners with twelve equivalent ReHf7Re5 cuboctahedra, edges with six equivalent ReHf7Re5 cuboctahedra, and faces with twenty ReHf6Re6 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf8Ni21 by Materials Project

Hf8Ni21 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to twelve Ni atoms. There are a spread of Hf–Ni bond distances ranging from 2.62–2.91 Å. In the second Hf site, Hf is bonded in a 12-coordinate geometry to thirteen Ni atoms. There are a spread of Hf–Ni bond distances ranging from 2.61–3.10 Å. In the third Hf site, Hf is bonded in a 12-coordinate geometry to twelve Ni atoms. There are a spread of Hf–Ni bond distances ranging from 2.59–2.86 Å. In the fourth Hf site, Hf is bonded in a 10-coordinate geometry to ten Ni atoms. There are a spread of Hf–Ni bond distances ranging from 2.59–2.76 Å. There are eleven inequivalent Ni sites. In the first Ni site, Ni is bonded to four Hf and eight Ni atoms to form face-sharing NiHf4Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.41–2.58 Å. In the second Ni site, Ni is bonded in a 4-coordinate geometry to four Hf and six Ni atoms. There are a spread of Ni–Ni bond distances ranging from 2.38–2.67 Å. In the third Ni site, Ni is bonded to five Hf and seven Ni atoms to form distorted NiHf5Ni7 cuboctahedra that share a cornercorner with one NiHf5Ni7 cuboctahedra, an edgeedge with one NiHf5Ni7 cuboctahedra, and faces with four NiHf4Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.43–2.53 Å. In the fourth Ni site, Ni is bonded in a 3-coordinate geometry to four Hf and six Ni atoms. There are a spread of Ni–Ni bond distances ranging from 2.42–2.84 Å. In the fifth Ni site, Ni is bonded in a 12-coordinate geometry to five Hf and seven Ni atoms. There are a spread of Ni–Ni bond distances ranging from 2.53–2.79 Å. In the sixth Ni site, Ni is bonded in a 12-coordinate geometry to four Hf and eight Ni atoms. There are a spread of Ni–Ni bond distances ranging from 2.50–2.70 Å. In the seventh Ni site, Ni is bonded in a 12-coordinate geometry to five Hf and seven Ni atoms. There are a spread of Ni–Ni bond distances ranging from 2.46–2.74 Å. In the eighth Ni site, Ni is bonded in a 12-coordinate geometry to four Hf and eight Ni atoms. There are a spread of Ni–Ni bond distances ranging from 2.57–2.82 Å. In the ninth Ni site, Ni is bonded to five Hf and seven Ni atoms to form distorted NiHf5Ni7 cuboctahedra that share a cornercorner with one NiHf5Ni7 cuboctahedra, an edgeedge with one NiHf5Ni7 cuboctahedra, and faces with four NiHf4Ni8 cuboctahedra. There are one shorter (2.54 Å) and one longer (2.58 Å) Ni–Ni bond lengths. In the tenth Ni site, Ni is bonded in a 5-coordinate geometry to five Hf and four Ni atoms. In the eleventh Ni site, Ni is bonded in a 12-coordinate geometry to four Hf and eight Ni atoms. The Ni–Ni bond length is 2.44 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf5FeTe3 by Materials Project

Hf5FeTe3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are five inequivalent Hf sites. In the first Hf site, Hf is bonded in a 5-coordinate geometry to one Fe and four Te atoms. The Hf–Fe bond length is 2.59 Å. There are two shorter (2.91 Å) and two longer (2.95 Å) Hf–Te bond lengths. In the second Hf site, Hf is bonded in a 12-coordinate geometry to two equivalent Fe and one Te atom. Both Hf–Fe bond lengths are 2.72 Å. The Hf–Te bond length is 3.00 Å. In the third Hf site, Hf is bonded to two equivalent Fe and three Te atoms to form distorted edge-sharing HfFe2Te3 square pyramids. Both Hf–Fe bond lengths are 2.61 Å. There are one shorter (2.98 Å) and two longer (3.04 Å) Hf–Te bond lengths. In the fourth Hf site, Hf is bonded in a distorted rectangular see-saw-like geometry to four Te atoms. There are a spread of Hf–Te bond distances ranging from 2.95–3.12 Å. In the fifth Hf site, Hf is bonded in a 5-coordinate geometry to two equivalent Fe and three Te atoms. Both Hf–Fe bond lengths are 2.59 Å. There are two shorter (2.98 Å) and one longer (3.00 Å) Hf–Te bond lengths. Fe is bonded in a 7-coordinate geometry to seven Hf atoms. There are three inequivalent Te sites. In the first Te site, Te is bonded in a 5-coordinate geometry to five Hf atoms. In the second Te site, Te is bonded in a 4-coordinate geometry to four Hf atoms. In the third Te site, Te is bonded in a 6-coordinate geometry to six Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfGa2Ni by Materials Project

HfNiGa2 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. there are four inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four equivalent Ni and eight Ga atoms. All Hf–Ni bond lengths are 2.67 Å. There are four shorter (2.92 Å) and four longer (3.04 Å) Hf–Ga bond lengths. In the second Hf site, Hf is bonded in a 12-coordinate geometry to four equivalent Ni and eight Ga atoms. All Hf–Ni bond lengths are 2.92 Å. There are four shorter (2.92 Å) and four longer (2.94 Å) Hf–Ga bond lengths. In the third Hf site, Hf is bonded in a 12-coordinate geometry to four Ni and ten Ga atoms. There are a spread of Hf–Ni bond distances ranging from 2.68–2.83 Å. There are a spread of Hf–Ga bond distances ranging from 2.84–3.34 Å. In the fourth Hf site, Hf is bonded in a 12-coordinate geometry to four Ni and nine Ga atoms. There are a spread of Hf–Ni bond distances ranging from 2.81–3.21 Å. There are a spread of Hf–Ga bond distances ranging from 2.81–3.12 Å. There are three inequivalent Ni sites. In the first Ni site, Ni is bonded in a 10-coordinate geometry to four Hf and six Ga atoms. There are a spread of Ni–Ga bond distances ranging from 2.44–2.61 Å. In the second Ni site, Ni is bonded in a 10-coordinate geometry to five Hf and five Ga atoms. There are a spread of Ni–Ga bond distances ranging from 2.47–2.59 Å. In the third Ni site, Ni is bonded in a 8-coordinate geometry to two equivalent Hf and eight Ga atoms. There are a spread of Ni–Ga bond distances ranging from 2.47–2.53 Å. There are four inequivalent Ga sites. In the first Ga site, Ga is bonded in a 11-coordinate geometry to five Hf, three Ni, and three Ga atoms. There are two shorter (2.77 Å) and one longer (3.00 Å) Ga–Ga bond lengths. In the second Ga site, Ga is bonded in a 3-coordinate geometry to four Hf, three Ni, and six Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.66–2.89 Å. In the third Ga site, Ga is bonded in a 11-coordinate geometry to six Hf, three Ni, and two equivalent Ga atoms. Both Ga–Ga bond lengths are 2.81 Å. In the fourth Ga site, Ga is bonded in a 10-coordinate geometry to four Hf, three Ni, and three Ga atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf5CoAs3 by Materials Project

Hf5CoAs3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are five inequivalent Hf sites. In the first Hf site, Hf is bonded to five As atoms to form distorted edge-sharing HfAs5 trigonal bipyramids. There are a spread of Hf–As bond distances ranging from 2.74–2.76 Å. In the second Hf site, Hf is bonded in a 6-coordinate geometry to one Co and five As atoms. The Hf–Co bond length is 2.87 Å. There are a spread of Hf–As bond distances ranging from 2.73–2.80 Å. In the third Hf site, Hf is bonded in a 6-coordinate geometry to three equivalent Co and four As atoms. There are two shorter (2.70 Å) and one longer (3.04 Å) Hf–Co bond lengths. There are a spread of Hf–As bond distances ranging from 2.73–2.84 Å. In the fourth Hf site, Hf is bonded in a 6-coordinate geometry to two equivalent Co and four As atoms. Both Hf–Co bond lengths are 2.54 Å. There are a spread of Hf–As bond distances ranging from 2.74–2.84 Å. In the fifth Hf site, Hf is bonded in a 4-coordinate geometry to one Co and four As atoms. The Hf–Co bond length is 2.60 Å. There are a spread of Hf–As bond distances ranging from 2.75–3.28 Å. Co is bonded in a 9-coordinate geometry to seven Hf and two equivalent As atoms. Both Co–As bond lengths are 2.43 Å. There are three inequivalent As sites. In the first As site, As is bonded in a 9-coordinate geometry to seven Hf and two equivalent Co atoms. In the second As site, As is bonded to seven Hf atoms to form distorted edge-sharing AsHf7 pentagonal bipyramids. In the third As site, As is bonded in a 7-coordinate geometry to eight Hf atoms.

36 MATERIALS SCIENCE↗