Materials Data on Ca3Sn2S7 by Materials Project

Abstract

Ca3Sn2S7 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to twelve S2- atoms to form distorted CaS12 cuboctahedra that share corners with four equivalent CaS12 cuboctahedra, faces with four equivalent CaS12 cuboctahedra, and faces with eight equivalent SnS6 octahedra. There are a spread of Ca–S bond distances ranging from 3.27–3.54 Å. In the second Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight S2- atoms. There are four shorter (3.24 Å) and four longer (3.26 Å) Ca–S bond lengths. In the third Ca2+ site, Ca2+ is bonded in a 1-coordinate geometry to five S2- atoms. There are a spread of Ca–S bond distances ranging from 2.69–3.20 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 1-coordinate geometry to five S2- atoms. There are a spread of Ca–S bond distances ranging from 2.69–3.17 Å. There are two inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to six S2- atoms to form distorted corner-sharing SnS6 octahedra. The corner-sharing octahedra tilt angles range from 0–25°. There are a spread of Sn–S bond distances ranging from 2.39–2.60 Å. In the second Sn4+ site, Sn4+ is bonded to six S2- atoms to form distorted SnS6 octahedra that share corners with five equivalent SnS6 octahedra and faces with four equivalent CaS12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–26°. There are a spread of Sn–S bond distances ranging from 2.41–2.65 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded in a linear geometry to two equivalent Sn4+ atoms. In the second S2- site, S2- is bonded in a linear geometry to four equivalent Ca2+ and two equivalent Sn4+ atoms. In the third S2- site, S2- is bonded in a linear geometry to one Ca2+ and one Sn4+ atom. In the fourth S2- site, S2- is bonded in a linear geometry to one Ca2+ and one Sn4+ atom. In the fifth S2- site, S2- is bonded to four Ca2+ and two equivalent Sn4+ atoms to form a mixture of distorted edge and corner-sharing SCa4Sn2 octahedra. The corner-sharing octahedra tilt angles range from 0–23°. In the sixth S2- site, S2- is bonded in a 6-coordinate geometry to four Ca2+ and two equivalent Sn4+ atoms. In the seventh S2- site, S2- is bonded in a 6-coordinate geometry to four Ca2+ and two equivalent Sn4+ atoms. In the eighth S2- site, S2- is bonded in a 6-coordinate geometry to four Ca2+ and two equivalent Sn4+ atoms.