Materials Data on Ca2SnS4 by Materials Project

Abstract

Ca2SnS4 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six S2- atoms to form distorted CaS6 pentagonal pyramids that share corners with four equivalent CaS6 pentagonal pyramids, corners with two equivalent SnS4 tetrahedra, edges with two equivalent CaS6 pentagonal pyramids, edges with two equivalent SnS4 tetrahedra, and faces with two equivalent CaS6 pentagonal pyramids. There are a spread of Ca–S bond distances ranging from 2.86–3.01 Å. In the second Ca2+ site, Ca2+ is bonded to six S2- atoms to form distorted CaS6 pentagonal pyramids that share corners with four equivalent CaS6 pentagonal pyramids, corners with four equivalent SnS4 tetrahedra, edges with two equivalent CaS6 pentagonal pyramids, an edgeedge with one SnS4 tetrahedra, and faces with two equivalent CaS6 pentagonal pyramids. There are a spread of Ca–S bond distances ranging from 2.81–3.00 Å. Sn4+ is bonded to four S2- atoms to form SnS4 tetrahedra that share corners with six CaS6 pentagonal pyramids and edges with three CaS6 pentagonal pyramids. There are two shorter (2.37 Å) and two longer (2.43 Å) Sn–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a T-shaped geometry to two Ca2+ and one Sn4+ atom. In the second S2- site, S2- is bonded in a T-shaped geometry to two Ca2+ and one Sn4+ atom. In the third S2- site, S2- is bonded to four Ca2+ and one Sn4+ atom to form a mixture of face, edge, and corner-sharing SCa4Sn square pyramids.