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DOE OSTI2020

Materials Data on HfAlMo by Materials Project

HfMoAl crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are eight inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five Mo, and seven Al atoms. There are a spread of Hf–Hf bond distances ranging from 3.24–3.30 Å. There are a spread of Hf–Mo bond distances ranging from 3.10–3.14 Å. There are a spread of Hf–Al bond distances ranging from 3.08–3.17 Å. In the second Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Mo, and five Al atoms. There are one shorter (3.24 Å) and one longer (3.30 Å) Hf–Hf bond lengths. There are a spread of Hf–Mo bond distances ranging from 3.08–3.15 Å. There are one shorter (3.06 Å) and four longer (3.15 Å) Hf–Al bond lengths. In the third Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Mo, and five Al atoms. There are two shorter (3.24 Å) and one longer (3.30 Å) Hf–Hf bond lengths. There are a spread of Hf–Mo bond distances ranging from 3.08–3.15 Å. There are one shorter (3.06 Å) and four longer (3.15 Å) Hf–Al bond lengths. In the fourth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five Mo, and seven Al atoms. The Hf–Hf bond length is 3.30 Å. There are a spread of Hf–Mo bond distances ranging from 3.10–3.14 Å. There are a spread of Hf–Al bond distances ranging from 3.08–3.17 Å. In the fifth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five Mo, and seven Al atoms. There are two shorter (3.24 Å) and one longer (3.27 Å) Hf–Hf bond lengths. There are a spread of Hf–Mo bond distances ranging from 3.10–3.14 Å. There are a spread of Hf–Al bond distances ranging from 3.08–3.17 Å. In the sixth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Mo, and five Al atoms. The Hf–Hf bond length is 3.24 Å. There are a spread of Hf–Mo bond distances ranging from 3.08–3.15 Å. There are one shorter (3.06 Å) and four longer (3.15 Å) Hf–Al bond lengths. In the seventh Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Mo, and five Al atoms. Both Hf–Hf bond lengths are 3.24 Å. There are a spread of Hf–Mo bond distances ranging from 3.08–3.15 Å. There are one shorter (3.06 Å) and four longer (3.15 Å) Hf–Al bond lengths. In the eighth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five Mo, and seven Al atoms. There are a spread of Hf–Mo bond distances ranging from 3.10–3.14 Å. There are a spread of Hf–Al bond distances ranging from 3.08–3.17 Å. There are three inequivalent Mo sites. In the first Mo site, Mo is bonded to six Hf and six Al atoms to form MoHf6Al6 cuboctahedra that share corners with four equivalent AlHf6Al2Mo4 cuboctahedra, corners with fourteen MoHf6Al6 cuboctahedra, edges with six MoHf6Al6 cuboctahedra, faces with four equivalent MoHf6Al2Mo4 cuboctahedra, and faces with fourteen AlHf6Al2Mo4 cuboctahedra. There are a spread of Mo–Al bond distances ranging from 2.61–2.71 Å. In the second Mo site, Mo is bonded to six Hf, four Mo, and two equivalent Al atoms to form distorted MoHf6Al2Mo4 cuboctahedra that share corners with eight MoHf6Al6 cuboctahedra, corners with ten AlHf6Al2Mo4 cuboctahedra, edges with two equivalent MoHf6Al2Mo4 cuboctahedra, edges with four equivalent AlHf6Al4Mo2 cuboctahedra, faces with eight AlHf6Al2Mo4 cuboctahedra, and faces with ten MoHf6Al6 cuboctahedra. There are a spread of Mo–Mo bond distances ranging from 2.56–2.73 Å. Both Mo–Al bond lengths are 2.69 Å. In the third Mo site, Mo is bonded to six Hf, four equivalent Mo, and two equivalent Al atoms to form distorted MoHf6Al2Mo4 cuboctahedra that share corners with six MoHf6Al6 cuboctahedra, corners with twelve AlHf6Al2Mo4 cuboctahedra, edges with six MoHf6Al6 cuboctahedra, faces with eight equivalent MoHf6Al2Mo4 cuboctahedra, and faces with ten AlHf6Al2Mo4 cuboctahedra. Both Mo–Al bond lengths are 2.72 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to six Hf, four Mo, and two equivalent Al atoms to form distorted AlHf6Al2Mo4 cuboctahedra that share corners with four equivalent AlHf6Al4Mo2 cuboctahedra, corners with eight MoHf6Al6 cuboctahedra, edges with six equivalent AlHf6Al2Mo4 cuboctahedra, faces with eight AlHf6Al2Mo4 cuboctahedra, and faces with twelve MoHf6Al6 cuboctahedra. Both Al–Al bond lengths are 2.69 Å. In the second Al site, Al is bonded to six Hf, two equivalent Mo, and four Al atoms to form distorted AlHf6Al4Mo2 cuboctahedra that share corners with eight AlHf6Al2Mo4 cuboctahedra, corners with ten MoHf6Al2Mo4 cuboctahedra, edges with two equivalent AlHf6Al4Mo2 cuboctahedra, edges with four equivalent MoHf6Al2Mo4 cuboctahedra, faces with eight MoHf6Al6 cuboctahedra, and faces with ten AlHf6Al2Mo4 cuboctahedra. There are one shorter (2.58 Å) and one longer (2.70 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfVSi by Materials Project

HfVSi crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are seven inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five V, and seven Si atoms. There are a spread of Hf–Hf bond distances ranging from 3.11–3.15 Å. There are a spread of Hf–V bond distances ranging from 2.99–3.04 Å. There are a spread of Hf–Si bond distances ranging from 2.96–3.01 Å. In the second Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven V, and five Si atoms. There are two shorter (3.14 Å) and one longer (3.20 Å) Hf–Hf bond lengths. There are a spread of Hf–V bond distances ranging from 2.98–3.05 Å. There are a spread of Hf–Si bond distances ranging from 2.84–3.05 Å. In the third Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven V, and five Si atoms. There are one shorter (3.11 Å) and two longer (3.14 Å) Hf–Hf bond lengths. There are a spread of Hf–V bond distances ranging from 2.98–3.05 Å. There are a spread of Hf–Si bond distances ranging from 2.84–3.05 Å. In the fourth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five V, and seven Si atoms. Both Hf–Hf bond lengths are 3.14 Å. There are a spread of Hf–V bond distances ranging from 2.99–3.04 Å. There are a spread of Hf–Si bond distances ranging from 2.96–3.01 Å. In the fifth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, five V, and seven Si atoms. There are one shorter (3.11 Å) and one longer (3.15 Å) Hf–Hf bond lengths. There are a spread of Hf–V bond distances ranging from 2.99–3.04 Å. There are a spread of Hf–Si bond distances ranging from 2.96–3.01 Å. In the sixth Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven V, and five Si atoms. The Hf–Hf bond length is 3.20 Å. There are a spread of Hf–V bond distances ranging from 2.98–3.05 Å. There are a spread of Hf–Si bond distances ranging from 2.84–3.05 Å. In the seventh Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven V, and five Si atoms. There are a spread of Hf–V bond distances ranging from 2.98–3.05 Å. There are a spread of Hf–Si bond distances ranging from 2.84–3.05 Å. There are three inequivalent V sites. In the first V site, V is bonded to six Hf and six Si atoms to form distorted VHf6Si6 cuboctahedra that share corners with four equivalent SiHf6V4Si2 cuboctahedra, corners with fourteen VHf6Si6 cuboctahedra, edges with six VHf6Si6 cuboctahedra, faces with four equivalent VHf6V4Si2 cuboctahedra, and faces with fourteen SiHf6V4Si2 cuboctahedra. There are a spread of V–Si bond distances ranging from 2.49–2.57 Å. In the second V site, V is bonded to six Hf, four V, and two equivalent Si atoms to form distorted VHf6V4Si2 cuboctahedra that share corners with eight VHf6Si6 cuboctahedra, corners with ten SiHf6V4Si2 cuboctahedra, edges with two equivalent VHf6V4Si2 cuboctahedra, edges with four equivalent SiHf6V2Si4 cuboctahedra, faces with eight SiHf6V4Si2 cuboctahedra, and faces with ten VHf6Si6 cuboctahedra. There are a spread of V–V bond distances ranging from 2.41–2.74 Å. Both V–Si bond lengths are 2.55 Å. In the third V site, V is bonded to six Hf, four equivalent V, and two equivalent Si atoms to form distorted VHf6V4Si2 cuboctahedra that share corners with six VHf6Si6 cuboctahedra, corners with twelve SiHf6V4Si2 cuboctahedra, edges with six VHf6Si6 cuboctahedra, faces with eight equivalent VHf6V4Si2 cuboctahedra, and faces with ten SiHf6V4Si2 cuboctahedra. Both V–Si bond lengths are 2.56 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to six Hf, four V, and two equivalent Si atoms to form distorted SiHf6V4Si2 cuboctahedra that share corners with four equivalent SiHf6V2Si4 cuboctahedra, corners with eight VHf6Si6 cuboctahedra, edges with six equivalent SiHf6V4Si2 cuboctahedra, faces with eight SiHf6V4Si2 cuboctahedra, and faces with twelve VHf6Si6 cuboctahedra. Both Si–Si bond lengths are 2.71 Å. In the second Si site, Si is bonded to six Hf, two equivalent V, and four Si atoms to form distorted SiHf6V2Si4 cuboctahedra that share corners with eight SiHf6V4Si2 cuboctahedra, corners with ten VHf6V4Si2 cuboctahedra, edges with two equivalent SiHf6V2Si4 cuboctahedra, edges with four equivalent VHf6V4Si2 cuboctahedra, faces with eight VHf6Si6 cuboctahedra, and faces with ten SiHf6V4Si2 cuboctahedra. There are one shorter (2.48 Å) and one longer (2.71 Å) Si–Si bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf54Os17 by Materials Project

Hf54Os17 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are twelve inequivalent Hf sites. In the first Hf site, Hf is bonded in a 1-coordinate geometry to one Hf and four Os atoms. The Hf–Hf bond length is 3.27 Å. There are a spread of Hf–Os bond distances ranging from 2.86–3.13 Å. In the second Hf site, Hf is bonded in a distorted linear geometry to two Os atoms. There are one shorter (2.85 Å) and one longer (2.91 Å) Hf–Os bond lengths. In the third Hf site, Hf is bonded in a distorted linear geometry to two Os atoms. There are one shorter (2.71 Å) and one longer (2.91 Å) Hf–Os bond lengths. In the fourth Hf site, Hf is bonded in a 2-coordinate geometry to eleven Hf and four Os atoms. There are a spread of Hf–Hf bond distances ranging from 3.02–3.25 Å. There are two shorter (3.04 Å) and two longer (3.28 Å) Hf–Os bond lengths. In the fifth Hf site, Hf is bonded in a 1-coordinate geometry to four Os atoms. There are a spread of Hf–Os bond distances ranging from 2.98–3.19 Å. In the sixth Hf site, Hf is bonded in a 1-coordinate geometry to four Os atoms. There are a spread of Hf–Os bond distances ranging from 2.62–3.03 Å. In the seventh Hf site, Hf is bonded in a distorted linear geometry to two Os atoms. There are one shorter (2.55 Å) and one longer (2.91 Å) Hf–Os bond lengths. In the eighth Hf site, Hf is bonded in a 1-coordinate geometry to one Hf and two Os atoms. There are one shorter (2.65 Å) and one longer (3.04 Å) Hf–Os bond lengths. In the ninth Hf site, Hf is bonded in a 4-coordinate geometry to four Os atoms. There are two shorter (2.83 Å) and two longer (3.12 Å) Hf–Os bond lengths. In the tenth Hf site, Hf is bonded in a 12-coordinate geometry to two equivalent Hf and five Os atoms. There are a spread of Hf–Os bond distances ranging from 2.72–2.87 Å. In the eleventh Hf site, Hf is bonded in a 4-coordinate geometry to four Os atoms. There are a spread of Hf–Os bond distances ranging from 2.71–2.80 Å. In the twelfth Hf site, Hf is bonded in a distorted linear geometry to two equivalent Os atoms. Both Hf–Os bond lengths are 2.78 Å. There are six inequivalent Os sites. In the first Os site, Os is bonded in a 12-coordinate geometry to ten Hf and two equivalent Os atoms. Both Os–Os bond lengths are 2.86 Å. In the second Os site, Os is bonded in a 12-coordinate geometry to eleven Hf and one Os atom. In the third Os site, Os is bonded in a 12-coordinate geometry to eleven Hf and one Os atom. The Os–Os bond length is 2.95 Å. In the fourth Os site, Os is bonded in a 9-coordinate geometry to nine Hf atoms. In the fifth Os site, Os is bonded in a 12-coordinate geometry to ten Hf and two equivalent Os atoms. In the sixth Os site, Os is bonded in a cuboctahedral geometry to twelve Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf8Mo5S by Materials Project

Hf8Mo5S crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are ten inequivalent Hf sites. In the first Hf site, Hf is bonded in a 1-coordinate geometry to five Mo and one S atom. There are a spread of Hf–Mo bond distances ranging from 2.93–3.10 Å. The Hf–S bond length is 2.57 Å. In the second Hf site, Hf is bonded in a 1-coordinate geometry to five Mo and one S atom. There are a spread of Hf–Mo bond distances ranging from 2.93–3.10 Å. The Hf–S bond length is 2.57 Å. In the third Hf site, Hf is bonded in a 1-coordinate geometry to six Mo and one S atom. There are a spread of Hf–Mo bond distances ranging from 2.94–3.40 Å. The Hf–S bond length is 2.73 Å. In the fourth Hf site, Hf is bonded in a 1-coordinate geometry to five Mo and one S atom. There are a spread of Hf–Mo bond distances ranging from 2.85–3.15 Å. The Hf–S bond length is 2.65 Å. In the fifth Hf site, Hf is bonded in a 1-coordinate geometry to five Mo and one S atom. There are a spread of Hf–Mo bond distances ranging from 2.84–3.15 Å. The Hf–S bond length is 2.65 Å. In the sixth Hf site, Hf is bonded in a 1-coordinate geometry to six Mo and one S atom. There are a spread of Hf–Mo bond distances ranging from 2.83–3.15 Å. The Hf–S bond length is 2.67 Å. In the seventh Hf site, Hf is bonded in a 5-coordinate geometry to four Mo and one S atom. There are a spread of Hf–Mo bond distances ranging from 2.77–3.09 Å. The Hf–S bond length is 2.87 Å. In the eighth Hf site, Hf is bonded in a linear geometry to two Mo atoms. There are one shorter (2.78 Å) and one longer (2.83 Å) Hf–Mo bond lengths. In the ninth Hf site, Hf is bonded in a linear geometry to two Mo atoms. There are one shorter (2.78 Å) and one longer (2.83 Å) Hf–Mo bond lengths. In the tenth Hf site, Hf is bonded in a 1-coordinate geometry to two Mo and one S atom. Both Hf–Mo bond lengths are 3.07 Å. The Hf–S bond length is 2.67 Å. There are nine inequivalent Mo sites. In the first Mo site, Mo is bonded to six Hf and six Mo atoms to form face-sharing MoHf6Mo6 cuboctahedra. There are a spread of Mo–Mo bond distances ranging from 2.66–2.72 Å. In the second Mo site, Mo is bonded in a 12-coordinate geometry to seven Hf and five Mo atoms. There are a spread of Mo–Mo bond distances ranging from 2.80–2.94 Å. In the third Mo site, Mo is bonded in a 12-coordinate geometry to seven Hf and five Mo atoms. There are one shorter (2.80 Å) and one longer (2.92 Å) Mo–Mo bond lengths. In the fourth Mo site, Mo is bonded in a 12-coordinate geometry to six Hf and six Mo atoms. Both Mo–Mo bond lengths are 2.71 Å. In the fifth Mo site, Mo is bonded in a 12-coordinate geometry to eight Hf and four Mo atoms. There are one shorter (2.82 Å) and one longer (2.98 Å) Mo–Mo bond lengths. In the sixth Mo site, Mo is bonded in a 12-coordinate geometry to eight Hf and four Mo atoms. The Mo–Mo bond length is 2.82 Å. In the seventh Mo site, Mo is bonded in a 12-coordinate geometry to eight Hf and four Mo atoms. In the eighth Mo site, Mo is bonded in a 12-coordinate geometry to nine Hf and three Mo atoms. The Mo–Mo bond length is 3.15 Å. In the ninth Mo site, Mo is bonded in a 12-coordinate geometry to nine Hf and three Mo atoms. There are two inequivalent S sites. In the first S site, S is bonded in a 7-coordinate geometry to seven Hf atoms. In the second S site, S is bonded in a 7-coordinate geometry to seven Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf27(Si3P5)2 by Materials Project

Hf27Si6P10 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are nine inequivalent Hf sites. In the first Hf site, Hf is bonded in a distorted rectangular see-saw-like geometry to one Si and three P atoms. The Hf–Si bond length is 2.87 Å. There are a spread of Hf–P bond distances ranging from 2.69–2.77 Å. In the second Hf site, Hf is bonded in a 4-coordinate geometry to three Si and one P atom. There are two shorter (2.67 Å) and one longer (2.86 Å) Hf–Si bond lengths. The Hf–P bond length is 2.65 Å. In the third Hf site, Hf is bonded to two equivalent Si and three P atoms to form distorted HfSi2P3 trigonal bipyramids that share corners with two equivalent HfP6 pentagonal pyramids, corners with two equivalent HfSi2P3 trigonal bipyramids, an edgeedge with one HfP6 pentagonal pyramid, edges with two equivalent HfSi2P3 trigonal bipyramids, and a faceface with one HfSi2P3 trigonal bipyramid. Both Hf–Si bond lengths are 2.73 Å. There are one shorter (2.61 Å) and two longer (2.69 Å) Hf–P bond lengths. In the fourth Hf site, Hf is bonded in a 4-coordinate geometry to three equivalent Si and two equivalent P atoms. There are two shorter (2.75 Å) and one longer (3.10 Å) Hf–Si bond lengths. Both Hf–P bond lengths are 2.72 Å. In the fifth Hf site, Hf is bonded in a 4-coordinate geometry to three Si and two equivalent P atoms. There are two shorter (2.74 Å) and one longer (3.23 Å) Hf–Si bond lengths. Both Hf–P bond lengths are 2.70 Å. In the sixth Hf site, Hf is bonded in a 6-coordinate geometry to two equivalent Si and four equivalent P atoms. Both Hf–Si bond lengths are 2.79 Å. All Hf–P bond lengths are 2.75 Å. In the seventh Hf site, Hf is bonded to six P atoms to form a mixture of distorted face, edge, and corner-sharing HfP6 pentagonal pyramids. There are two shorter (2.68 Å) and four longer (2.75 Å) Hf–P bond lengths. In the eighth Hf site, Hf is bonded to six P atoms to form distorted HfP6 pentagonal pyramids that share corners with four equivalent HfP6 pentagonal pyramids, corners with four equivalent HfSi2P3 trigonal bipyramids, edges with four HfP6 pentagonal pyramids, edges with two equivalent HfSi2P3 trigonal bipyramids, and faces with three equivalent HfP6 pentagonal pyramids. There are two shorter (2.69 Å) and four longer (2.76 Å) Hf–P bond lengths. In the ninth Hf site, Hf is bonded in a distorted square co-planar geometry to two equivalent Si and two equivalent P atoms. Both Hf–Si bond lengths are 2.95 Å. Both Hf–P bond lengths are 2.68 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to nine Hf atoms. In the second Si site, Si is bonded in a 9-coordinate geometry to nine Hf atoms. There are four inequivalent P sites. In the first P site, P is bonded in a 8-coordinate geometry to eight Hf atoms. In the second P site, P is bonded in a 8-coordinate geometry to eight Hf atoms. In the third P site, P is bonded in a 8-coordinate geometry to eight Hf atoms. In the fourth P site, P is bonded to seven Hf atoms to form a mixture of distorted edge and corner-sharing PHf7 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2Se3 by Materials Project

Hf2Se3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Hf sites. In the first Hf site, Hf is bonded to six Se atoms to form a mixture of edge, face, and corner-sharing HfSe6 octahedra. The corner-sharing octahedra tilt angles range from 8–47°. There are a spread of Hf–Se bond distances ranging from 2.59–2.79 Å. In the second Hf site, Hf is bonded to six Se atoms to form a mixture of edge, face, and corner-sharing HfSe6 octahedra. The corner-sharing octahedra tilt angles range from 8–47°. There are a spread of Hf–Se bond distances ranging from 2.58–2.79 Å. In the third Hf site, Hf is bonded to six Se atoms to form a mixture of edge, face, and corner-sharing HfSe6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of Hf–Se bond distances ranging from 2.62–2.76 Å. In the fourth Hf site, Hf is bonded to six Se atoms to form a mixture of edge and corner-sharing HfSe6 octahedra. The corner-sharing octahedra tilt angles range from 8–47°. There are a spread of Hf–Se bond distances ranging from 2.63–2.74 Å. In the fifth Hf site, Hf is bonded to six Se atoms to form a mixture of edge and corner-sharing HfSe6 octahedra. The corner-sharing octahedra tilt angles range from 8–47°. There are a spread of Hf–Se bond distances ranging from 2.62–2.74 Å. In the sixth Hf site, Hf is bonded to six Se atoms to form a mixture of edge and corner-sharing HfSe6 octahedra. The corner-sharing octahedra tilt angles range from 8–47°. There are a spread of Hf–Se bond distances ranging from 2.63–2.74 Å. In the seventh Hf site, Hf is bonded to six Se atoms to form a mixture of edge, face, and corner-sharing HfSe6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of Hf–Se bond distances ranging from 2.62–2.75 Å. In the eighth Hf site, Hf is bonded to six Se atoms to form a mixture of edge and corner-sharing HfSe6 octahedra. The corner-sharing octahedra tilt angles range from 8–47°. There are a spread of Hf–Se bond distances ranging from 2.63–2.73 Å. There are twelve inequivalent Se sites. In the first Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the second Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the third Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the fourth Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the fifth Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the sixth Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the seventh Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the eighth Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the ninth Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the tenth Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the eleventh Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms. In the twelfth Se site, Se is bonded in a rectangular see-saw-like geometry to four Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2Ga3Co by Materials Project

Hf2CoGa3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Hf sites. In the first Hf site, Hf is bonded in a 5-coordinate geometry to one Co and eight Ga atoms. The Hf–Co bond length is 3.24 Å. There are a spread of Hf–Ga bond distances ranging from 2.70–3.22 Å. In the second Hf site, Hf is bonded in a 7-coordinate geometry to one Co and nine Ga atoms. The Hf–Co bond length is 2.85 Å. There are a spread of Hf–Ga bond distances ranging from 2.70–3.37 Å. In the third Hf site, Hf is bonded in a 9-coordinate geometry to one Co and eight Ga atoms. The Hf–Co bond length is 2.84 Å. There are a spread of Hf–Ga bond distances ranging from 2.73–3.03 Å. In the fourth Hf site, Hf is bonded in a 9-coordinate geometry to one Co and eight Ga atoms. The Hf–Co bond length is 2.87 Å. There are a spread of Hf–Ga bond distances ranging from 2.75–3.11 Å. In the fifth Hf site, Hf is bonded in a 7-coordinate geometry to three Co and nine Ga atoms. There are a spread of Hf–Co bond distances ranging from 2.70–3.43 Å. There are a spread of Hf–Ga bond distances ranging from 2.73–3.43 Å. In the sixth Hf site, Hf is bonded in a 12-coordinate geometry to three Co and nine Ga atoms. There are a spread of Hf–Co bond distances ranging from 2.74–3.21 Å. There are a spread of Hf–Ga bond distances ranging from 2.71–3.35 Å. There are three inequivalent Co sites. In the first Co site, Co is bonded in a 12-coordinate geometry to two Hf and six Ga atoms. There are a spread of Co–Ga bond distances ranging from 2.46–2.56 Å. In the second Co site, Co is bonded in a 12-coordinate geometry to two Hf, one Co, and five Ga atoms. The Co–Co bond length is 2.69 Å. There are a spread of Co–Ga bond distances ranging from 2.37–2.67 Å. In the third Co site, Co is bonded in a 12-coordinate geometry to six Hf, one Co, and five Ga atoms. There are a spread of Co–Ga bond distances ranging from 2.43–2.77 Å. There are nine inequivalent Ga sites. In the first Ga site, Ga is bonded in a 9-coordinate geometry to six Hf, two Co, and one Ga atom. The Ga–Ga bond length is 2.63 Å. In the second Ga site, Ga is bonded in a 9-coordinate geometry to six Hf, one Co, and two Ga atoms. There are one shorter (2.59 Å) and one longer (2.67 Å) Ga–Ga bond lengths. In the third Ga site, Ga is bonded in a 9-coordinate geometry to six Hf, one Co, and two Ga atoms. There are one shorter (2.54 Å) and one longer (2.61 Å) Ga–Ga bond lengths. In the fourth Ga site, Ga is bonded in a 9-coordinate geometry to six Hf, two Co, and one Ga atom. The Ga–Ga bond length is 2.64 Å. In the fifth Ga site, Ga is bonded in a 11-coordinate geometry to five Hf, three Co, and three Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.56–2.76 Å. In the sixth Ga site, Ga is bonded in a 10-coordinate geometry to four Hf, three Co, and three Ga atoms. There are a spread of Ga–Ga bond distances ranging from 2.56–2.69 Å. In the seventh Ga site, Ga is bonded to six Hf, two Co, and four Ga atoms to form face-sharing GaHf6Ga4Co2 cuboctahedra. In the eighth Ga site, Ga is bonded in a 12-coordinate geometry to six Hf, one Co, and five Ga atoms. The Ga–Ga bond length is 2.82 Å. In the ninth Ga site, Ga is bonded to six Hf, one Co, and five Ga atoms to form distorted face-sharing GaHf6Ga5Co cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf3AlGe5 by Materials Project

Hf3AlGe5 is Zirconium Disilicide-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are six inequivalent Hf sites. In the first Hf site, Hf is bonded in a 10-coordinate geometry to ten Ge atoms. There are a spread of Hf–Ge bond distances ranging from 2.78–3.20 Å. In the second Hf site, Hf is bonded in a 10-coordinate geometry to two equivalent Al and eight Ge atoms. Both Hf–Al bond lengths are 2.92 Å. There are a spread of Hf–Ge bond distances ranging from 2.75–3.12 Å. In the third Hf site, Hf is bonded in a 10-coordinate geometry to two equivalent Al and eight Ge atoms. Both Hf–Al bond lengths are 2.93 Å. There are a spread of Hf–Ge bond distances ranging from 2.74–3.06 Å. In the fourth Hf site, Hf is bonded in a 10-coordinate geometry to ten Ge atoms. There are a spread of Hf–Ge bond distances ranging from 2.78–3.20 Å. In the fifth Hf site, Hf is bonded in a 10-coordinate geometry to two equivalent Al and eight Ge atoms. Both Hf–Al bond lengths are 2.95 Å. There are a spread of Hf–Ge bond distances ranging from 2.74–3.05 Å. In the sixth Hf site, Hf is bonded in a 10-coordinate geometry to two equivalent Al and eight Ge atoms. Both Hf–Al bond lengths are 2.94 Å. There are a spread of Hf–Ge bond distances ranging from 2.75–3.11 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 8-coordinate geometry to four Hf and four equivalent Ge atoms. All Al–Ge bond lengths are 2.69 Å. In the second Al site, Al is bonded in a 8-coordinate geometry to four Hf and four equivalent Ge atoms. All Al–Ge bond lengths are 2.69 Å. There are ten inequivalent Ge sites. In the first Ge site, Ge is bonded in a 8-coordinate geometry to four Hf and four equivalent Ge atoms. All Ge–Ge bond lengths are 2.69 Å. In the second Ge site, Ge is bonded to four Hf and four equivalent Al atoms to form a mixture of distorted corner and face-sharing GeHf4Al4 hexagonal bipyramids. In the third Ge site, Ge is bonded to four Hf and four equivalent Al atoms to form a mixture of distorted corner and face-sharing GeHf4Al4 hexagonal bipyramids. In the fourth Ge site, Ge is bonded in a 8-coordinate geometry to four Hf and four equivalent Ge atoms. In the fifth Ge site, Ge is bonded in a 4-coordinate geometry to six Hf and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.67 Å. In the sixth Ge site, Ge is bonded in a 4-coordinate geometry to six Hf and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.67 Å. In the seventh Ge site, Ge is bonded in a 4-coordinate geometry to six Hf and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.70 Å. In the eighth Ge site, Ge is bonded in a 4-coordinate geometry to six Hf and two equivalent Ge atoms. In the ninth Ge site, Ge is bonded in a 4-coordinate geometry to six Hf and two equivalent Ge atoms. In the tenth Ge site, Ge is bonded in a 4-coordinate geometry to six Hf and two equivalent Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf27P16 by Materials Project

Hf27P16 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are nine inequivalent Hf sites. In the first 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 2.69–3.13 Å. In the second Hf site, Hf is bonded in a 6-coordinate geometry to six P atoms. There are two shorter (2.74 Å) and four longer (2.79 Å) Hf–P bond lengths. In the third Hf site, Hf is bonded to six P atoms to form a mixture of distorted corner, edge, and face-sharing HfP6 pentagonal pyramids. There are two shorter (2.67 Å) and four longer (2.75 Å) Hf–P bond lengths. In the fourth Hf site, Hf is bonded to six P atoms to form distorted HfP6 pentagonal pyramids that share corners with four equivalent HfP6 pentagonal pyramids, corners with four equivalent HfP5 trigonal bipyramids, edges with four HfP6 pentagonal pyramids, edges with two equivalent HfP5 trigonal bipyramids, and faces with three equivalent HfP6 pentagonal pyramids. There are two shorter (2.67 Å) and four longer (2.74 Å) Hf–P bond lengths. In the fifth Hf site, Hf is bonded in a distorted square co-planar geometry to four P atoms. There are two shorter (2.58 Å) and two longer (2.88 Å) Hf–P bond lengths. In the sixth Hf site, Hf is bonded in a 5-coordinate geometry to five P atoms. There are four shorter (2.71 Å) and one longer (3.07 Å) Hf–P bond lengths. In the seventh Hf site, Hf is bonded to five P atoms to form distorted HfP5 trigonal bipyramids that share corners with two equivalent HfP6 pentagonal pyramids, corners with two equivalent HfP5 trigonal bipyramids, an edgeedge with one HfP6 pentagonal pyramid, edges with two equivalent HfP5 trigonal bipyramids, and a faceface with one HfP5 trigonal bipyramid. There are a spread of Hf–P bond distances ranging from 2.59–2.69 Å. In the eighth 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 2.61–2.82 Å. In the ninth Hf site, Hf is bonded in a square co-planar geometry to four P atoms. There are a spread of Hf–P bond distances ranging from 2.66–2.79 Å. There are six inequivalent P sites. In the first P site, P is bonded in a 8-coordinate geometry to eight Hf atoms. In the second P site, P is bonded to seven Hf atoms to form a mixture of distorted corner and edge-sharing PHf7 pentagonal bipyramids. In the third P site, P is bonded in a 8-coordinate geometry to eight Hf atoms. In the fourth P site, P is bonded in a 8-coordinate geometry to eight Hf atoms. In the fifth P site, P is bonded in a 9-coordinate geometry to nine Hf atoms. In the sixth P site, P is bonded in a 9-coordinate geometry to nine Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KHf6CCl15 by Materials Project

KHf6CCl15 crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. K is bonded in a distorted q6 geometry to ten Cl atoms. There are a spread of K–Cl bond distances ranging from 3.36–3.52 Å. There are five inequivalent Hf sites. In the first Hf site, Hf is bonded to one C and five Cl atoms to form a mixture of corner and edge-sharing HfCCl5 octahedra. The corner-sharing octahedral tilt angles are 0°. The Hf–C bond length is 2.22 Å. There are four shorter (2.50 Å) and one longer (2.66 Å) Hf–Cl bond lengths. In the second Hf site, Hf is bonded to one C and five Cl atoms to form a mixture of corner and edge-sharing HfCCl5 octahedra. The corner-sharing octahedra tilt angles range from 0–43°. The Hf–C bond length is 2.23 Å. There are a spread of Hf–Cl bond distances ranging from 2.50–2.74 Å. In the third Hf site, Hf is bonded to one C and five Cl atoms to form a mixture of corner and edge-sharing HfCCl5 octahedra. The corner-sharing octahedra tilt angles range from 1–48°. The Hf–C bond length is 2.27 Å. There are a spread of Hf–Cl bond distances ranging from 2.51–2.66 Å. In the fourth Hf site, Hf is bonded to one C and five Cl atoms to form a mixture of corner and edge-sharing HfCCl5 octahedra. The corner-sharing octahedral tilt angles are 0°. The Hf–C bond length is 2.22 Å. There are four shorter (2.53 Å) and one longer (2.64 Å) Hf–Cl bond lengths. In the fifth Hf site, Hf is bonded to one C and five Cl atoms to form a mixture of corner and edge-sharing HfCCl5 octahedra. The corner-sharing octahedra tilt angles range from 0–48°. The Hf–C bond length is 2.27 Å. There are a spread of Hf–Cl bond distances ranging from 2.51–2.66 Å. There are two inequivalent C sites. In the first C site, C is bonded in an octahedral geometry to six Hf atoms. In the second C site, C is bonded in an octahedral geometry to six Hf atoms. There are eleven inequivalent Cl sites. In the first Cl site, Cl is bonded in a rectangular see-saw-like geometry to two equivalent K and two equivalent Hf atoms. In the second Cl site, Cl is bonded in a distorted square co-planar geometry to two equivalent K and two Hf atoms. In the third Cl site, Cl is bonded in a 3-coordinate geometry to one K and two Hf atoms. In the fourth Cl site, Cl is bonded in an L-shaped geometry to two equivalent Hf atoms. In the fifth Cl site, Cl is bonded in an L-shaped geometry to two equivalent Hf atoms. In the sixth Cl site, Cl is bonded in an L-shaped geometry to two equivalent Hf atoms. In the seventh Cl site, Cl is bonded in an L-shaped geometry to two equivalent Hf atoms. In the eighth Cl site, Cl is bonded in a 3-coordinate geometry to one K and two Hf atoms. In the ninth Cl site, Cl is bonded in a bent 120 degrees geometry to two Hf atoms. In the tenth Cl site, Cl is bonded in a 3-coordinate geometry to one K and two Hf atoms. In the eleventh Cl site, Cl is bonded in a 3-coordinate geometry to one K and two Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf6Cr5Si7 by Materials Project

Hf6Cr5Si7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are six inequivalent Hf sites. In the first Hf site, Hf is bonded in a 7-coordinate geometry to two equivalent Cr and seven Si atoms. Both Hf–Cr bond lengths are 2.98 Å. There are a spread of Hf–Si bond distances ranging from 2.69–2.83 Å. In the second Hf site, Hf is bonded in a 7-coordinate geometry to two equivalent Cr and seven Si atoms. Both Hf–Cr bond lengths are 2.98 Å. There are a spread of Hf–Si bond distances ranging from 2.78–2.85 Å. In the third Hf site, Hf is bonded in a 6-coordinate geometry to three Cr and six Si atoms. There are two shorter (2.85 Å) and one longer (2.96 Å) Hf–Cr bond lengths. There are a spread of Hf–Si bond distances ranging from 2.66–2.84 Å. In the fourth Hf site, Hf is bonded in a 6-coordinate geometry to two equivalent Cr and six Si atoms. Both Hf–Cr bond lengths are 2.83 Å. There are a spread of Hf–Si bond distances ranging from 2.66–2.83 Å. In the fifth Hf site, Hf is bonded in a 10-coordinate geometry to five Cr and five Si atoms. There are a spread of Hf–Cr bond distances ranging from 2.94–3.07 Å. There are a spread of Hf–Si bond distances ranging from 2.79–2.95 Å. In the sixth Hf site, Hf is bonded to seven Si atoms to form distorted HfSi7 pentagonal bipyramids that share corners with four equivalent CrHf5Cr3Si4 cuboctahedra, corners with two equivalent HfSi7 pentagonal bipyramids, and edges with two equivalent HfSi7 pentagonal bipyramids. There are a spread of Hf–Si bond distances ranging from 2.67–2.89 Å. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded in a 7-coordinate geometry to one Cr and six Si atoms. The Cr–Cr bond length is 2.42 Å. There are a spread of Cr–Si bond distances ranging from 2.44–2.66 Å. In the second Cr site, Cr is bonded in a 12-coordinate geometry to four Hf, two equivalent Cr, and three Si atoms. Both Cr–Cr bond lengths are 2.38 Å. There are one shorter (2.36 Å) and two longer (2.42 Å) Cr–Si bond lengths. In the third Cr site, Cr is bonded to five Hf, three Cr, and four Si atoms to form distorted CrHf5Cr3Si4 cuboctahedra that share corners with two equivalent CrHf5Cr3Si4 cuboctahedra, corners with two equivalent HfSi7 pentagonal bipyramids, and faces with two equivalent CrHf5Cr3Si4 cuboctahedra. There are one shorter (2.53 Å) and one longer (2.56 Å) Cr–Cr bond lengths. There are a spread of Cr–Si bond distances ranging from 2.44–2.50 Å. There are six inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to five Hf and four Cr atoms. In the second Si site, Si is bonded in a 9-coordinate geometry to five Hf and four equivalent Cr atoms. In the third Si site, Si is bonded in a 10-coordinate geometry to seven Hf, one Cr, and two equivalent Si atoms. There are one shorter (2.50 Å) and one longer (2.59 Å) Si–Si bond lengths. In the fourth Si site, Si is bonded in a 9-coordinate geometry to four Hf and five Cr atoms. In the fifth Si site, Si is bonded in a 9-coordinate geometry to five Hf and four Cr atoms. In the sixth Si site, Si is bonded in a 9-coordinate geometry to five Hf and four Cr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2N2O by Materials Project

Hf2ON2 is Ilmenite-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Hf4+ sites. In the first Hf4+ site, Hf4+ is bonded to 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 49–57°. There are a spread of Hf–N bond distances ranging from 2.08–2.20 Å. There are one shorter (2.11 Å) and two longer (2.21 Å) Hf–O bond lengths. In the second 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 53–59°. There are a spread of Hf–N bond distances ranging from 2.07–2.21 Å. There are one shorter (2.27 Å) and one longer (2.29 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra 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 2.09–2.18 Å. There are one shorter (2.28 Å) and one longer (2.30 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with six HfN4O2 octahedra 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 2.11–2.22 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.20 Å. 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 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 2.14–2.21 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 and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.12–2.24 Å. There are one shorter (2.20 Å) and one longer (2.23 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 edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.11–2.19 Å. There are one shorter (2.23 Å) and one longer (2.25 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Hf–N bond distances ranging from 2.13–2.27 Å. There are one shorter (2.11 Å) and one longer (2.25 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. The Hf–O bond length is 2.24 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 HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 55–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.18 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 edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Hf–N bond distances ranging from 2.09–2.18 Å. There are one shorter (2.22 Å) and one longer (2.28 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.14–2.25 Å. The Hf–O bond length is 2.21 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.24 Å. There are one shorter (2.15 Å) and one longer (2.19 Å) Hf–O bond lengths. In the fourteenth 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 2.10–2.23 Å. The Hf–O bond length is 2.31 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of Hf–N bond distances ranging from 2.09–2.22 Å. There are one shorter (2.20 Å) and one longer (2.25 Å) Hf–O bond lengths. In the sixteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. 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 (2.20 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 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 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 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 tetrahedra that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 tetrahedra, 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 two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share 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 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 corners with three NHf4 tetrahedra, corners with three 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 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, 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, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the tenth N3- site, N3- is bonded to four Hf4+ atoms to form 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 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 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 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 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 thirteenth 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 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 tetrahedra, and edges with three NHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with 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 edges with two NHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one OHf4 tetrahedra, corners with four 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. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid

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 a mixture of distorted 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 2.11–2.22 Å. There are one shorter (2.20 Å) and one longer (2.22 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. 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 (2.27 Å) Hf–O bond lengths. In the third 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 51–55°. There are a spread of Hf–N bond distances ranging from 2.12–2.25 Å. There are one shorter (2.11 Å) and one longer (2.24 Å) Hf–O bond lengths. In the fourth 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 52–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.17 Å. There are one shorter (2.26 Å) and one longer (2.27 Å) Hf–O bond lengths. In the fifth 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 54–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.22 Å. The Hf–O bond length is 2.29 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 five HfN5O octahedra, a cornercorner with one HfN4O2 pentagonal pyramid, 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 2.08–2.21 Å. There are one shorter (2.22 Å) and one longer (2.29 Å) Hf–O bond lengths. In the seventh 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 48–57°. There are a spread of Hf–N bond distances ranging from 2.13–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.11–2.18 Å. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.13–2.22 Å. There are one shorter (2.13 Å) and one longer (2.21 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Hf–N bond distances ranging from 2.13–2.21 Å. There are one shorter (2.15 Å) and one longer (2.19 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 corner and edge-sharing HfN4O2 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Hf–N bond distances ranging from 2.15–2.19 Å. There are one shorter (2.16 Å) and one longer (2.18 Å) Hf–O bond lengths. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Hf–N bond distances ranging from 2.08–2.20 Å. There are one shorter (2.23 Å) and one longer (2.31 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted corner and edge-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There are a spread of Hf–N bond distances ranging from 2.10–2.22 Å. The Hf–O bond length is 2.29 Å. In the thirteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted corner and edge-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.11–2.29 Å. There are one shorter (2.13 Å) and one longer (2.24 Å) Hf–O bond lengths. In the fourteenth 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 52–56°. There are a spread of Hf–N bond distances ranging from 2.08–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.15–2.25 Å. In the fifteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN5O octahedra, and an edgeedge with one HfN4O2 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Hf–N bond distances ranging from 2.09–2.15 Å. There are one shorter (2.29 Å) and one longer (2.32 Å) Hf–O bond lengths. In the sixteenth 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 48–58°. There are a spread of Hf–N bond distances ranging from 2.12–2.22 Å. There are one shorter (2.20 Å) and one longer (2.21 Å) Hf–O bond lengths. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with nine 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, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one 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 tetrahedra that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, 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 corners with two NHf4 tetrahedra, corners with three 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 seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the tenth 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 NHf4 trigonal pyramid, 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 two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the twelfth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 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 fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, 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 five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the sixteenth 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 two OHf4 trigonal pyramids, corners with nine NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three OHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three 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 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 three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, and edges with four 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 two NHf4 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 fourth O2- site, O2- is bonded to four Hf4+ atoms to form distorted OH

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 six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are one shorter (2.07 Å) and one longer (2.09 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.12–2.22 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 HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–54°. There are one shorter (2.13 Å) and two longer (2.15 Å) Hf–N bond lengths. There are a spread of Hf–O bond distances ranging from 2.10–2.21 Å. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–54°. There are a spread of Hf–N bond distances ranging from 2.13–2.22 Å. There are one shorter (2.13 Å) and one 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 and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.07–2.17 Å. There are one shorter (2.31 Å) and one longer (2.38 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.30 Å. There are one shorter (2.19 Å) and one longer (2.22 Å) Hf–O bond lengths. In the sixth 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 52–57°. There are a spread of Hf–N bond distances ranging from 2.14–2.19 Å. There are one shorter (2.13 Å) and one longer (2.19 Å) Hf–O bond lengths. In the seventh Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. The Hf–O bond length is 2.28 Å. In the eighth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN2O4 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 49–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.21 Å. There are one shorter (2.20 Å) and one longer (2.27 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Hf–N bond distances ranging from 2.08–2.18 Å. There are one shorter (2.23 Å) and one longer (2.31 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.22 Å. The Hf–O bond length is 2.32 Å. In the eleventh 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 50–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.21 Å. There are one shorter (2.11 Å) and two longer (2.21 Å) Hf–O bond lengths. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN2O4 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 2.35 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 52–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.17 Å. There are one shorter (2.24 Å) and one longer (2.28 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 and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. There are a spread of Hf–N bond distances ranging from 2.11–2.21 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.21 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 six HfN3O3 octahedra and edges with six HfN2O4 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.24 Å. The Hf–O bond length is 2.23 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 HfN2O4 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–56°. There are a spread of Hf–N bond distances ranging from 2.12–2.26 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 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 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 OHf4 trigonal pyramids, corners with nine 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 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 fourth 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 fifth 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, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, 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 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 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 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share 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 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 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 tenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the eleventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 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 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 OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with four OHf4 trigonal pyramids, corners with eight 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 corners with three OHf4 trigonal pyramids, corners with nine NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, 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 corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the third O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, and edges with four NHf4 trigonal pyramids. In the fourth O2- site, O2- is bonded to four Hf4+ a

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 HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–54°. There are a spread of Hf–N bond distances ranging from 2.11–2.24 Å. There are one shorter (2.12 Å) and one longer (2.23 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.12–2.17 Å. There are one shorter (2.23 Å) and one longer (2.25 Å) Hf–O bond lengths. In the third 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 53–57°. There are a spread of Hf–N bond distances ranging from 2.09–2.20 Å. There are one shorter (2.18 Å) and one longer (2.29 Å) Hf–O bond lengths. 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 53–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.26 Å. There are one shorter (2.12 Å) and one longer (2.21 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 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 2.07–2.13 Å. There are a spread of Hf–O bond distances ranging from 2.18–2.28 Å. In the sixth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.17 Å. Both Hf–O bond lengths are 2.27 Å. In the seventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.17 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 a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.10–2.19 Å. There are one shorter (2.23 Å) and one longer (2.27 Å) Hf–O bond lengths. In the ninth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.18 Å. There are one shorter (2.24 Å) and one longer (2.26 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 six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are one shorter (2.08 Å) and three longer (2.16 Å) Hf–N bond lengths. There are one shorter (2.20 Å) and one longer (2.32 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 distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–54°. There are a spread of Hf–N bond distances ranging from 2.13–2.20 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.16 Å. In the twelfth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.29 Å. The Hf–O bond length is 2.22 Å. In the thirteenth 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 50–58°. There are a spread of Hf–N bond distances ranging from 2.10–2.27 Å. There are one shorter (2.19 Å) and one longer (2.21 Å) Hf–O bond lengths. In the fourteenth 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 52–56°. 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 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 50–54°. 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 2.14–2.21 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.12–2.23 Å. The Hf–O bond length is 2.32 Å. 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 five NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with eight NHf4 trigonal pyramids, and edges with four OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fourth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the 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, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share 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 seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, 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 five NHf4 trigonal pyramids, corners with seven OHf4 trigonal pyramids, edges with three NHf4 tetrahedra, and an edgeedge with one OHf4 trigonal pyramid. In the ninth 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 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, 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 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 thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form NHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with eight NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with two NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. 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 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 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, and edges with three 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 three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, and edges with four 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 four OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the fifth O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with five OHf4 trigonal

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 four HfN4O2 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Hf–N bond distances ranging from 2.08–2.21 Å. There are one shorter (2.11 Å) and two longer (2.20 Å) Hf–O bond lengths. In the second Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.12–2.18 Å. There are one shorter (2.22 Å) and one longer (2.24 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with six HfN4O2 octahedra, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.17 Å. There are one shorter (2.29 Å) and one longer (2.31 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 HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.27 Å. There are one shorter (2.14 Å) and one longer (2.24 Å) Hf–O bond lengths. In the fifth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form distorted HfN4O2 octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Hf–N bond distances ranging from 2.10–2.24 Å. There are one shorter (2.19 Å) and one longer (2.21 Å) Hf–O bond lengths. 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 53–56°. There are a spread of Hf–N bond distances ranging from 2.10–2.18 Å. There are one shorter (2.26 Å) and one longer (2.27 Å) Hf–O bond lengths. In the seventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with five HfN4O2 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, edges with five HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Hf–N bond distances ranging from 2.08–2.20 Å. There are one 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 HfN4O2 octahedra that share corners with six HfN3O3 octahedra, edges with four HfN4O2 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Hf–N bond distances ranging from 2.10–2.21 Å. There are one shorter (2.24 Å) and one longer (2.25 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 four HfN3O3 octahedra, corners with two HfN3O3 pentagonal pyramids, 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 2.09–2.18 Å. There are one shorter (2.21 Å) and one longer (2.28 Å) Hf–O bond lengths. In the tenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra, edges with four HfN4O2 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.12–2.24 Å. The Hf–O bond length is 2.32 Å. In the eleventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 octahedra that share corners with four HfN4O2 octahedra, corners with two HfN3O3 pentagonal pyramids, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–53°. There are a spread of Hf–N bond distances ranging from 2.12–2.21 Å. There are a spread of Hf–O bond distances ranging from 2.12–2.16 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 HfN3O3 octahedra, and an edgeedge with one HfN3O3 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.14–2.26 Å. The Hf–O bond length is 2.23 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 five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Hf–N bond distances ranging from 2.07–2.18 Å. There are a spread of Hf–O bond distances ranging from 2.15–2.22 Å. In the fourteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with five HfN3O3 octahedra, a cornercorner with one HfN3O3 pentagonal pyramid, and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. 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 fifteenth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form distorted HfN3O3 pentagonal pyramids 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 one shorter (2.09 Å) and two longer (2.16 Å) Hf–N bond lengths. There are two shorter (2.15 Å) and one longer (2.23 Å) Hf–O bond lengths. In the sixteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra, edges with four HfN4O2 octahedra, and edges with two HfN3O3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Hf–N bond distances ranging from 2.13–2.22 Å. The Hf–O bond length is 2.30 Å. 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 five NHf4 trigonal pyramids, corners with seven 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 second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with seven NHf4 trigonal pyramids, and edges with four OHf4 trigonal pyramids. In the third N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four 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 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 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 five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the sixth 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 seventh 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 OHf4 trigonal pyramid. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the ninth 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 tenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four 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 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 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 thirteenth 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 fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fifteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with four NHf4 tetrahedra, a cornercorner with one OHf4 trigonal pyramid, corners with seven NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the sixteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, edges wit

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 HfN3O3 octahedra 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 2.08–2.19 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 four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.10–2.19 Å. There are one shorter (2.21 Å) and one longer (2.25 Å) Hf–O bond lengths. In the third 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 53–56°. There are a spread of Hf–N bond distances ranging from 2.08–2.17 Å. There are one shorter (2.29 Å) and one longer (2.31 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 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 2.10–2.23 Å. There are a spread of Hf–O bond distances ranging from 2.11–2.23 Å. In the fifth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. 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 2.11–2.23 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 53–56°. There are a spread of Hf–N bond distances ranging from 2.11–2.20 Å. The Hf–O bond length is 2.27 Å. In the seventh Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form HfN3O3 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are two shorter (2.07 Å) and one longer (2.12 Å) Hf–N bond lengths. There are one shorter (2.21 Å) and two longer (2.26 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form distorted HfN5O octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.12–2.25 Å. The Hf–O bond length is 2.34 Å. In the ninth 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 54–58°. There are a spread of Hf–N bond distances ranging from 2.10–2.23 Å. The Hf–O bond length is 2.30 Å. In the tenth 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 49–56°. There are a spread of Hf–N bond distances ranging from 2.12–2.20 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.17 Å. In the eleventh Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN3O3 octahedra and edges with six HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Hf–N bond distances ranging from 2.10–2.18 Å. There are one shorter (2.26 Å) and one longer (2.27 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 52–58°. There are a spread of Hf–N bond distances ranging from 2.15–2.23 Å. The Hf–O bond length is 2.22 Å. In the thirteenth 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 49–57°. There are a spread of Hf–N bond distances ranging from 2.06–2.20 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.24 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 six HfN4O2 octahedra and edges with six HfN5O octahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of Hf–N bond distances ranging from 2.16–2.18 Å. There are one shorter (2.16 Å) and one longer (2.17 Å) Hf–O bond lengths. In the fifteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 49–57°. 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 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 53–58°. There are a spread of Hf–N bond distances ranging from 2.12–2.24 Å. There are one shorter (2.18 Å) and one longer (2.21 Å) Hf–O bond lengths. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one NHf4 trigonal pyramid, and edges with two OHf4 trigonal pyramids. In the second N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share corners with two NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the third 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 NHf4 trigonal pyramid, and edges with three OHf4 trigonal pyramids. In the fourth 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 fifth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the sixth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 tetrahedra that share a cornercorner with one NHf4 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 seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five 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 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 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 ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share corners with three NHf4 tetrahedra, corners with 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 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 five OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the 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 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 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 six NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the fourteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share 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 three NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with six NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the sixteenth 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, 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 OHf4 trigonal pyramids, corners with seven NHf4 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 OHf4 trigonal pyramids that share corners with five OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, and edges with three NHf4 trigonal pyramids. In the 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 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 fourth O2- site, O2- is bonded to four Hf4+ atoms to form OHf4 trigonal pyramids that share corners with two NHf4 tetrahedra, corners with three OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In

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 a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of Hf–N bond distances ranging from 2.09–2.24 Å. There are one shorter (2.18 Å) and one longer (2.27 Å) Hf–O bond lengths. In the second 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 51–57°. There are a spread of Hf–N bond distances ranging from 2.10–2.18 Å. There are one shorter (2.23 Å) and one longer (2.26 Å) Hf–O bond lengths. In the third Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Hf–N bond distances ranging from 2.09–2.19 Å. There are one shorter (2.23 Å) and one longer (2.28 Å) Hf–O bond lengths. In the fourth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form HfN4O2 octahedra that share corners with six HfN4O2 octahedra and edges with six HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Hf–N bond distances ranging from 2.08–2.20 Å. There are one shorter (2.24 Å) and one longer (2.29 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 edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–53°. There are a spread of Hf–N bond distances ranging from 2.13–2.16 Å. There are a spread of Hf–O bond distances ranging from 2.09–2.21 Å. In the sixth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Hf–N bond distances ranging from 2.13–2.21 Å. There are one shorter (2.15 Å) and one longer (2.17 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 distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Hf–N bond distances ranging from 2.11–2.22 Å. There are one shorter (2.23 Å) and one longer (2.25 Å) Hf–O bond lengths. In the eighth Hf4+ site, Hf4+ is bonded to three N3- and three O2- atoms to form a mixture of distorted edge and corner-sharing HfN3O3 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Hf–N bond distances ranging from 2.07–2.14 Å. There are two shorter (2.19 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 a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 52–58°. There are a spread of Hf–N bond distances ranging from 2.13–2.23 Å. The Hf–O bond length is 2.24 Å. In the tenth 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 52–57°. There are a spread of Hf–N bond distances ranging from 2.11–2.22 Å. There are a spread of Hf–O bond distances ranging from 2.13–2.19 Å. In the eleventh Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Hf–N bond distances ranging from 2.11–2.25 Å. The Hf–O bond length is 2.31 Å. In the twelfth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of Hf–N bond distances ranging from 2.08–2.18 Å. There are one shorter (2.18 Å) and one longer (2.34 Å) Hf–O bond lengths. In the thirteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 54–58°. There are a spread of Hf–N bond distances ranging from 2.09–2.20 Å. There are one shorter (2.26 Å) and one longer (2.28 Å) Hf–O bond lengths. In the fourteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Hf–N bond distances ranging from 2.15–2.20 Å. There are one shorter (2.16 Å) and one longer (2.18 Å) Hf–O bond lengths. In the fifteenth Hf4+ site, Hf4+ is bonded to five N3- and one O2- atom to form a mixture of distorted edge and corner-sharing HfN5O octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of Hf–N bond distances ranging from 2.12–2.22 Å. The Hf–O bond length is 2.28 Å. In the sixteenth Hf4+ site, Hf4+ is bonded to four N3- and two O2- atoms to form a mixture of distorted edge and corner-sharing HfN4O2 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Hf–N bond distances ranging from 2.11–2.19 Å. There are one shorter (2.20 Å) and one longer (2.24 Å) Hf–O bond lengths. There are sixteen inequivalent N3- sites. In the first N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 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 six NHf4 trigonal pyramids, corners with six OHf4 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 tetrahedra that share corners with two OHf4 trigonal pyramids, corners with ten 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 six NHf4 trigonal pyramids, corners with six OHf4 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 a cornercorner with one NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with nine 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 four OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the seventh N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the eighth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 trigonal pyramids. In the ninth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six 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 a cornercorner with one NHf4 tetrahedra, corners with two OHf4 trigonal pyramids, corners with nine 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 a cornercorner with one NHf4 tetrahedra, corners with five NHf4 trigonal pyramids, corners with six OHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three NHf4 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, and edges with four NHf4 trigonal pyramids. In the thirteenth N3- site, N3- is bonded to four Hf4+ atoms to form distorted NHf4 trigonal pyramids that share a cornercorner with one NHf4 tetrahedra, corners with four OHf4 trigonal pyramids, corners with seven NHf4 trigonal pyramids, 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 corners with six 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 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 corners with two OHf4 trigonal pyramids, corners with ten 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 four OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges with two NHf4 trigonal pyramids. In the second O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with four OHf4 trigonal pyramids, corners with eight NHf4 trigonal pyramids, and edges with four 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 two OHf4 trigonal pyramids, corners with nine NHf4 trigonal pyramids, an edgeedge with one OHf4 trigonal pyramid, and edges with three 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 OHf4 trigonal pyramids, corners with ten NHf4 trigonal pyramids, edges with two NHf4 trigonal pyramids, and edges with two OHf4 trigonal pyramids. In the fifth O2- site, O2- is bonded to four Hf4+ atoms to form distorted OHf4 trigonal pyramids that share corners with two OHf4 trigonal pyramids, corners with ten NHf4 trigonal pyramids, an edgeedge with one NHf4 tetrahedra, an edgeedge with one OHf4 trigonal pyramid, and edges wi

36 MATERIALS SCIENCE↗