Materials Data on Nb7S8 by Materials Project
Nb7S8 crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are three inequivalent Nb+2.29+ sites. In the first Nb+2.29+ site, Nb+2.29+ is bonded to six S2- atoms to form a mixture of edge, face, and corner-sharing NbS6 octahedra. The corner-sharing octahedra tilt angles range from 47–49°. There are a spread of Nb–S bond distances ranging from 2.49–2.64 Å. In the second Nb+2.29+ site, Nb+2.29+ is bonded to six S2- atoms to form a mixture of edge, face, and corner-sharing NbS6 octahedra. The corner-sharing octahedra tilt angles range from 39–50°. There are a spread of Nb–S bond distances ranging from 2.48–2.60 Å. In the third Nb+2.29+ site, Nb+2.29+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing NbS6 octahedra. The corner-sharing octahedra tilt angles range from 39–50°. There are three shorter (2.49 Å) and three longer (2.54 Å) Nb–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to six Nb+2.29+ atoms to form distorted corner-sharing SNb6 pentagonal pyramids. In the second S2- site, S2- is bonded to six Nb+2.29+ atoms to form distorted corner-sharing SNb6 pentagonal pyramids. In the third S2- site, S2- is bonded in a distorted pentagonal planar geometry to five Nb+2.29+ atoms. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to five Nb+2.29+ atoms.