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.