Materials Data on Nb4CrSe8 by Materials Project

Nb4CrSe8 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Nb+3.50+ sites. In the first Nb+3.50+ site, Nb+3.50+ is bonded to six equivalent Se2- atoms to form NbSe6 octahedra that share edges with six equivalent NbSe6 octahedra and faces with two equivalent CrSe6 pentagonal pyramids. All Nb–Se bond lengths are 2.65 Å. In the second Nb+3.50+ site, Nb+3.50+ is bonded to six Se2- atoms to form NbSe6 octahedra that share corners with four equivalent CrSe6 pentagonal pyramids and edges with six NbSe6 octahedra. There are two shorter (2.62 Å) and four longer (2.64 Å) Nb–Se bond lengths. Cr2+ is bonded to six equivalent Se2- atoms to form distorted CrSe6 pentagonal pyramids that share corners with twelve equivalent NbSe6 octahedra and faces with two equivalent NbSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. All Cr–Se bond lengths are 2.68 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Nb+3.50+ and one Cr2+ atom to form a mixture of distorted corner and edge-sharing SeNb3Cr trigonal pyramids. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.50+ atoms.