Materials Data on Ca7Sn3S13 by Materials Project
Ca7Sn3S13 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 9-coordinate geometry to nine S2- atoms. There are a spread of Ca–S bond distances ranging from 2.92–3.49 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Ca–S bond distances ranging from 2.76–3.40 Å. In the third Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Ca–S bond distances ranging from 2.79–3.19 Å. In the fourth Ca2+ site, Ca2+ is bonded to seven S2- atoms to form distorted CaS7 pentagonal bipyramids that share corners with two SnS4 tetrahedra, edges with two SnS4 tetrahedra, and a faceface with one CaS7 pentagonal bipyramid. There are a spread of Ca–S bond distances ranging from 2.86–3.22 Å. There are two inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to four S2- atoms to form SnS4 tetrahedra that share a cornercorner with one CaS7 pentagonal bipyramid and an edgeedge with one CaS7 pentagonal bipyramid. There are a spread of Sn–S bond distances ranging from 2.39–2.43 Å. In the second Sn4+ site, Sn4+ is bonded to four S2- atoms to form SnS4 tetrahedra that share corners with two equivalent CaS7 pentagonal bipyramids and edges with two equivalent CaS7 pentagonal bipyramids. There are a spread of Sn–S bond distances ranging from 2.37–2.42 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to three Ca2+ and one Sn4+ atom. In the second S2- site, S2- is bonded in a 6-coordinate geometry to five Ca2+ and one Sn4+ atom. In the third S2- site, S2- is bonded in a 4-coordinate geometry to three Ca2+ and one Sn4+ atom. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to four Ca2+ and one Sn4+ atom. In the fifth S2- site, S2- is bonded in a 6-coordinate geometry to five Ca2+ and one Sn4+ atom. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to four Ca2+ and one Sn4+ atom. In the seventh S2- site, S2- is bonded in a 5-coordinate geometry to four Ca2+ and one Sn4+ atom. In the eighth S2- site, S2- is bonded in a distorted square pyramidal geometry to five Ca2+ atoms.