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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on HfNbB4 by Materials Project

HfNbB4 is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Hf4+ is bonded to twelve equivalent B+1.50- atoms to form HfB12 cuboctahedra that share edges with four equivalent NbB12 cuboctahedra, edges with eight equivalent HfB12 cuboctahedra, faces with two equivalent HfB12 cuboctahedra, and faces with six equivalent NbB12 cuboctahedra. All Hf–B bond lengths are 2.48 Å. Nb2+ is bonded to twelve equivalent B+1.50- atoms to form NbB12 cuboctahedra that share edges with four equivalent HfB12 cuboctahedra, edges with eight equivalent NbB12 cuboctahedra, faces with two equivalent NbB12 cuboctahedra, and faces with six equivalent HfB12 cuboctahedra. There are eight shorter (2.48 Å) and four longer (2.49 Å) Nb–B bond lengths. B+1.50- is bonded in a 9-coordinate geometry to three equivalent Hf4+, three equivalent Nb2+, and three equivalent B+1.50- atoms. There is one shorter (1.80 Å) and two longer (1.81 Å) B–B bond length.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf(Nb2B3)4 by Materials Project

Hf(Nb2B3)4 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Hf4+ is bonded to twelve B2- atoms to form a mixture of edge and face-sharing HfB12 cuboctahedra. There are eight shorter (2.48 Å) and four longer (2.53 Å) Hf–B bond lengths. There are four inequivalent Nb+2.50+ sites. In the first Nb+2.50+ site, Nb+2.50+ is bonded in a 7-coordinate geometry to seven B2- atoms. There are a spread of Nb–B bond distances ranging from 2.40–2.58 Å. In the second Nb+2.50+ site, Nb+2.50+ is bonded in a 7-coordinate geometry to seven B2- atoms. There are a spread of Nb–B bond distances ranging from 2.39–2.59 Å. In the third Nb+2.50+ site, Nb+2.50+ is bonded in a 7-coordinate geometry to seven B2- atoms. There are a spread of Nb–B bond distances ranging from 2.39–2.58 Å. In the fourth Nb+2.50+ site, Nb+2.50+ is bonded to twelve B2- atoms to form a mixture of edge and face-sharing NbB12 cuboctahedra. There are eight shorter (2.48 Å) and four longer (2.51 Å) Nb–B bond lengths. There are six inequivalent B2- sites. In the first B2- site, B2- is bonded in a 9-coordinate geometry to six Nb+2.50+ and three B2- atoms. There is one shorter (1.82 Å) and two longer (1.85 Å) B–B bond length. In the second B2- site, B2- is bonded in a 9-coordinate geometry to six Nb+2.50+ and three B2- atoms. Both B–B bond lengths are 1.85 Å. In the third B2- site, B2- is bonded in a 9-coordinate geometry to four equivalent Hf4+, two equivalent Nb+2.50+, and three B2- atoms. There is one shorter (1.84 Å) and two longer (1.85 Å) B–B bond length. In the fourth B2- site, B2- is bonded in a 9-coordinate geometry to seven Nb+2.50+ and two equivalent B2- atoms. In the fifth B2- site, B2- is bonded in a 9-coordinate geometry to seven Nb+2.50+ and two equivalent B2- atoms. In the sixth B2- site, B2- is bonded in a 9-coordinate geometry to two equivalent Hf4+, five Nb+2.50+, and two equivalent B2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfNbB4 by Materials Project

HfNbB4 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Hf4+ is bonded to twelve equivalent B+1.50- atoms to form HfB12 cuboctahedra that share edges with twelve equivalent NbB12 cuboctahedra, faces with two equivalent NbB12 cuboctahedra, and faces with six equivalent HfB12 cuboctahedra. All Hf–B bond lengths are 2.50 Å. Nb2+ is bonded to twelve equivalent B+1.50- atoms to form NbB12 cuboctahedra that share edges with twelve equivalent HfB12 cuboctahedra, faces with two equivalent HfB12 cuboctahedra, and faces with six equivalent NbB12 cuboctahedra. All Nb–B bond lengths are 2.47 Å. B+1.50- is bonded in a 9-coordinate geometry to three equivalent Hf4+, three equivalent Nb2+, and three equivalent B+1.50- atoms. All B–B bond lengths are 1.81 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfNbB2 by Materials Project

HfNbB2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Hf4+ is bonded in a 7-coordinate geometry to seven B3- atoms. There are a spread of Hf–B bond distances ranging from 2.49–2.67 Å. Nb2+ is bonded in a 7-coordinate geometry to seven B3- atoms. There are a spread of Nb–B bond distances ranging from 2.43–2.81 Å. There are two inequivalent B3- sites. In the first B3- site, B3- is bonded in a 9-coordinate geometry to three equivalent Hf4+, four equivalent Nb2+, and two equivalent B3- atoms. Both B–B bond lengths are 1.87 Å. In the second B3- site, B3- is bonded in a 9-coordinate geometry to four equivalent Hf4+, three equivalent Nb2+, and two equivalent B3- atoms.

36 MATERIALS SCIENCE↗