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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Nb10(SiB)3 by Materials Project

Nb10(BSi)3 crystallizes in the orthorhombic Fmm2 space group. The structure is three-dimensional. there are four inequivalent Nb+2.10+ sites. In the first Nb+2.10+ site, Nb+2.10+ is bonded to two B3- and three Si4- atoms to form NbSi3B2 trigonal bipyramids that share corners with four equivalent NbSi3B3 octahedra, corners with twelve NbSi3B2 trigonal bipyramids, edges with seven NbSi3B2 trigonal bipyramids, faces with two equivalent NbSi3B3 octahedra, and a faceface with one NbSi3B2 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 42–62°. There are one shorter (2.51 Å) and one longer (2.53 Å) Nb–B bond lengths. There are a spread of Nb–Si bond distances ranging from 2.54–2.69 Å. In the second Nb+2.10+ site, Nb+2.10+ is bonded to three B3- and two equivalent Si4- atoms to form NbSi2B3 trigonal bipyramids that share corners with four equivalent NbSi3B3 octahedra, corners with twelve NbSi3B2 trigonal bipyramids, edges with seven NbSi3B2 trigonal bipyramids, faces with two equivalent NbSi3B3 octahedra, and a faceface with one NbSi2B3 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 42–60°. There are two shorter (2.44 Å) and one longer (2.49 Å) Nb–B bond lengths. Both Nb–Si bond lengths are 2.69 Å. In the third Nb+2.10+ site, Nb+2.10+ is bonded to two equivalent B3- and three Si4- atoms to form NbSi3B2 trigonal bipyramids that share corners with four equivalent NbSi3B3 octahedra, corners with twelve NbSi3B2 trigonal bipyramids, edges with seven NbSi3B2 trigonal bipyramids, faces with two equivalent NbSi3B3 octahedra, and a faceface with one NbSi3B2 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 44–63°. Both Nb–B bond lengths are 2.44 Å. There are one shorter (2.61 Å) and two longer (2.72 Å) Nb–Si bond lengths. In the fourth Nb+2.10+ site, Nb+2.10+ is bonded to three B3- and three Si4- atoms to form distorted NbSi3B3 octahedra that share corners with six equivalent NbSi3B3 octahedra, corners with sixteen NbSi3B2 trigonal bipyramids, and faces with eight NbSi3B2 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 2–56°. There are a spread of Nb–B bond distances ranging from 2.48–2.57 Å. There are one shorter (2.57 Å) and two longer (2.94 Å) Nb–Si bond lengths. There are two inequivalent B3- sites. In the first B3- site, B3- is bonded in a 9-coordinate geometry to eight Nb+2.10+ and one B3- atom. The B–B bond length is 2.06 Å. In the second B3- site, B3- is bonded in a 9-coordinate geometry to eight Nb+2.10+ and one Si4- atom. The B–Si bond length is 2.19 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to eight Nb+2.10+ and one B3- atom. In the second Si4- site, Si4- is bonded in a 10-coordinate geometry to ten Nb+2.10+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb5SiB2 by Materials Project

Nb5SiB2 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. there are two inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded to four equivalent B3- and two equivalent Si4- atoms to form distorted NbSi2B4 octahedra that share corners with six equivalent NbSi2B4 octahedra, corners with sixteen equivalent NbSi2B3 trigonal bipyramids, and faces with eight equivalent NbSi2B3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–57°. All Nb–B bond lengths are 2.53 Å. Both Nb–Si bond lengths are 2.92 Å. In the second Nb2+ site, Nb2+ is bonded to three equivalent B3- and two equivalent Si4- atoms to form NbSi2B3 trigonal bipyramids that share corners with four equivalent NbSi2B4 octahedra, corners with twelve equivalent NbSi2B3 trigonal bipyramids, edges with seven equivalent NbSi2B3 trigonal bipyramids, faces with two equivalent NbSi2B4 octahedra, and a faceface with one NbSi2B3 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 42–61°. There are two shorter (2.42 Å) and one longer (2.51 Å) Nb–B bond lengths. Both Nb–Si bond lengths are 2.68 Å. B3- is bonded in a 9-coordinate geometry to eight Nb2+ and one B3- atom. The B–B bond length is 2.01 Å. Si4- is bonded in a 10-coordinate geometry to ten Nb2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb5Si3B by Materials Project

Nb5BSi3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent Nb3+ sites. In the first Nb3+ site, Nb3+ is bonded to six equivalent Si4- atoms to form distorted NbSi6 octahedra that share corners with six equivalent NbSi6 octahedra, corners with twelve equivalent NbSi5B2 pentagonal bipyramids, edges with three equivalent NbSi6 octahedra, faces with two equivalent NbSi6 octahedra, and faces with six equivalent NbSi5B2 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 33°. All Nb–Si bond lengths are 2.69 Å. In the second Nb3+ site, Nb3+ is bonded to two equivalent B3- and five equivalent Si4- atoms to form distorted NbSi5B2 pentagonal bipyramids that share corners with eight equivalent NbSi6 octahedra, corners with eight equivalent NbSi5B2 pentagonal bipyramids, edges with two equivalent NbSi5B2 pentagonal bipyramids, faces with four equivalent NbSi6 octahedra, and faces with six equivalent NbSi5B2 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 44–56°. Both Nb–B bond lengths are 2.31 Å. There are a spread of Nb–Si bond distances ranging from 2.69–2.91 Å. B3- is bonded to six equivalent Nb3+ atoms to form face-sharing BNb6 octahedra. Si4- is bonded in a 9-coordinate geometry to nine Nb3+ atoms.

36 MATERIALS SCIENCE↗