Materials Data on Sr3Sn2S7 by Materials Project
Sr3Sn2S7 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.04–3.36 Å. In the second Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to eight S2- atoms. There are four shorter (3.20 Å) and four longer (3.22 Å) Sr–S bond lengths. Sn4+ is bonded to five S2- atoms to form corner-sharing SnS5 trigonal bipyramids. There are a spread of Sn–S bond distances ranging from 2.41–2.94 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Sn4+ atoms. In the second S2- site, S2- is bonded to four Sr2+ and one Sn4+ atom to form distorted SSr4Sn square pyramids that share corners with three equivalent SSr4Sn2 octahedra, corners with eight SSr4Sn square pyramids, an edgeedge with one SSr4Sn2 octahedra, edges with five SSr4Sn square pyramids, and a faceface with one SSr4Sn square pyramid. The corner-sharing octahedra tilt angles range from 7–33°. In the third S2- site, S2- is bonded to four Sr2+ and one Sn4+ atom to form distorted SSr4Sn square pyramids that share corners with two equivalent SSr4Sn2 octahedra, corners with eight SSr4Sn square pyramids, edges with five SSr4Sn square pyramids, a faceface with one SSr4Sn2 octahedra, and a faceface with one SSr4Sn square pyramid. The corner-sharing octahedral tilt angles are 59°. In the fourth S2- site, S2- is bonded to four equivalent Sr2+ and two equivalent Sn4+ atoms to form SSr4Sn2 octahedra that share corners with ten SSr4Sn square pyramids, edges with two equivalent SSr4Sn2 octahedra, edges with two equivalent SSr4Sn square pyramids, and faces with two equivalent SSr4Sn square pyramids.