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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on HfTaB4 by Materials Project

HfTaB4 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Hf is bonded to twelve equivalent B atoms to form HfB12 cuboctahedra that share edges with twelve equivalent TaB12 cuboctahedra, faces with two equivalent TaB12 cuboctahedra, and faces with six equivalent HfB12 cuboctahedra. All Hf–B bond lengths are 2.51 Å. Ta is bonded to twelve equivalent B atoms to form TaB12 cuboctahedra that share edges with twelve equivalent HfB12 cuboctahedra, faces with two equivalent HfB12 cuboctahedra, and faces with six equivalent TaB12 cuboctahedra. All Ta–B bond lengths are 2.45 Å. B is bonded in a 9-coordinate geometry to three equivalent Hf, three equivalent Ta, and three equivalent B atoms. All B–B bond lengths are 1.80 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Materials Data on HfTa5B4 by Materials Project

HfTa5B4 crystallizes in the tetragonal P4/m space group. The structure is three-dimensional. Hf is bonded in a distorted square co-planar geometry to four equivalent B atoms. All Hf–B bond lengths are 2.56 Å. There are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 6-coordinate geometry to six equivalent B atoms. There are a spread of Ta–B bond distances ranging from 2.45–2.55 Å. In the second Ta site, Ta is bonded in a square co-planar geometry to four equivalent B atoms. All Ta–B bond lengths are 2.55 Å. B is bonded in a 9-coordinate geometry to one Hf, seven Ta, and one B atom. The B–B bond length is 1.88 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfTaB2 by Materials Project

HfTaB2 is delta Molybdenum Boride-derived structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. Hf is bonded in a 7-coordinate geometry to seven B atoms. There are a spread of Hf–B bond distances ranging from 2.48–2.67 Å. Ta is bonded in a 7-coordinate geometry to seven B atoms. There are a spread of Ta–B bond distances ranging from 2.42–2.81 Å. There are two inequivalent B sites. In the first B site, B is bonded in a 9-coordinate geometry to three equivalent Hf, four equivalent Ta, and two equivalent B atoms. Both B–B bond lengths are 1.86 Å. In the second B site, B is bonded in a 9-coordinate geometry to four equivalent Hf, three equivalent Ta, and two equivalent B atoms.

36 MATERIALS SCIENCE↗