Materials Data on Nb4CrS8 by Materials Project
Nb4CrS8 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 S2- atoms to form distorted NbS6 pentagonal pyramids that share corners with four equivalent CrS6 octahedra and edges with six NbS6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 48°. There are two shorter (2.46 Å) and four longer (2.52 Å) Nb–S bond lengths. In the second Nb+3.50+ site, Nb+3.50+ is bonded to six equivalent S2- atoms to form distorted NbS6 pentagonal pyramids that share edges with six equivalent NbS6 pentagonal pyramids and faces with two equivalent CrS6 octahedra. All Nb–S bond lengths are 2.49 Å. Cr2+ is bonded to six equivalent S2- atoms to form CrS6 octahedra that share corners with twelve equivalent NbS6 pentagonal pyramids and faces with two equivalent NbS6 pentagonal pyramids. All Cr–S bond lengths are 2.41 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Nb+3.50+ and one Cr2+ atom. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Nb+3.50+ atoms.