DOI: 10.17188/1678053
title: Materials Data on Ca3Er2(SnS4)3 by Materials Project

description: Ca3Er2Sn3S12 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two 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 2.90–3.35 Å. In the second Ca2+ site, Ca2+ is bonded to seven S2- atoms to form distorted CaS7 pentagonal bipyramids that share corners with two equivalent SnS6 octahedra, corners with two equivalent ErS7 pentagonal bipyramids, edges with four equivalent SnS6 octahedra, and edges with two equivalent CaS7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ca–S bond distances ranging from 2.81–2.93 Å. Er3+ is bonded to seven S2- atoms to form distorted ErS7 pentagonal bipyramids that share corners with two equivalent SnS6 octahedra, a cornercorner with one CaS7 pentagonal bipyramid, a cornercorner with one ErS7 pentagonal bipyramid, edges with four SnS6 octahedra, and edges with two equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 49°. There are a spread of Er–S bond distances ranging from 2.76–2.89 Å. There are two inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to six S2- atoms to form SnS6 octahedra that share corners with two equivalent CaS7 pentagonal bipyramids, edges with two equivalent SnS6 octahedra, and edges with four equivalent ErS7 pentagonal bipyramids. There are a spread of Sn–S bond distances ranging from 2.55–2.64 Å. In the second Sn4+ site, Sn4+ is bonded to six S2- atoms to form SnS6 octahedra that share corners with two equivalent ErS7 pentagonal bipyramids, edges with two equivalent SnS6 octahedra, edges with two equivalent CaS7 pentagonal bipyramids, and edges with two equivalent ErS7 pentagonal bipyramids. There are a spread of Sn–S bond distances ranging from 2.50–2.63 Å. There are seven inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Er3+ and two equivalent Sn4+ atoms. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Ca2+, one Er3+, and two equivalent Sn4+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to three Ca2+ and two equivalent Sn4+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Ca2+, one Er3+, and two equivalent Sn4+ atoms to form distorted SCa2ErSn2 trigonal bipyramids that share corners with four SCa2Er2Sn square pyramids, corners with four equivalent SCa2ErSn2 trigonal bipyramids, edges with four SCa4Sn square pyramids, and edges with four equivalent SCa2Er2Sn trigonal bipyramids. In the fifth S2- site, S2- is bonded to two equivalent Ca2+, two equivalent Er3+, and one Sn4+ atom to form distorted SCa2Er2Sn square pyramids that share corners with three SCa2Er2Sn square pyramids, corners with six SCa2ErSn2 trigonal bipyramids, edges with three SCa2Er2Sn square pyramids, and edges with four SCa2ErSn2 trigonal bipyramids. In the sixth S2- site, S2- is bonded to two equivalent Ca2+, two equivalent Er3+, and one Sn4+ atom to form distorted SCa2Er2Sn trigonal bipyramids that share corners with seven SCa4Sn square pyramids, edges with three SCa2Er2Sn square pyramids, and edges with six SCa2ErSn2 trigonal bipyramids. In the seventh S2- site, S2- is bonded to four Ca2+ and one Sn4+ atom to form distorted SCa4Sn square pyramids that share corners with four SCa2Er2Sn square pyramids, corners with five SCa2ErSn2 trigonal bipyramids, edges with four SCa2Er2Sn square pyramids, and edges with three SCa2ErSn2 trigonal bipyramids.