Materials Data on Ca(ErS2)2 by Materials Project

Abstract

Ca(ErS2)2 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Ca2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Ca–S bond distances ranging from 2.77–3.24 Å. There are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing ErS6 octahedra. The corner-sharing octahedra tilt angles range from 8–54°. There are a spread of Er–S bond distances ranging from 2.65–2.77 Å. In the second Er3+ site, Er3+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing ErS6 octahedra. The corner-sharing octahedra tilt angles range from 8–54°. There are a spread of Er–S bond distances ranging from 2.65–2.78 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Ca2+ and two Er3+ atoms to form distorted SCa2Er2 tetrahedra that share corners with two equivalent SCaEr4 square pyramids, corners with two equivalent SCa2Er2 tetrahedra, corners with ten SCa2Er3 trigonal bipyramids, edges with two equivalent SCaEr4 square pyramids, and edges with two SCa2Er3 trigonal bipyramids. In the second S2- site, S2- is bonded to two equivalent Ca2+ and three Er3+ atoms to form distorted SCa2Er3 trigonal bipyramids that share corners with two equivalent SCaEr4 square pyramids, corners with five equivalent SCa2Er2 tetrahedra, corners with two equivalent SCa2Er3 trigonal bipyramids, edges with three equivalent SCaEr4 square pyramids, an edgeedge with one SCa2Er2 tetrahedra, and edges with five SCa2Er3 trigonal bipyramids. In the third S2- site, S2- is bonded to two equivalent Ca2+ and three Er3+ atoms to form distorted SCa2Er3 trigonal bipyramids that share corners with six equivalent SCaEr4 square pyramids, corners with five equivalent SCa2Er2 tetrahedra, corners with two equivalent SCa2Er3 trigonal bipyramids, an edgeedge with one SCaEr4 square pyramid, an edgeedge with one SCa2Er2 tetrahedra, and edges with five SCa2Er3 trigonal bipyramids. In the fourth S2- site, S2- is bonded to one Ca2+ and four Er3+ atoms to form distorted SCaEr4 square pyramids that share corners with two equivalent SCa2Er2 tetrahedra, corners with eight SCa2Er3 trigonal bipyramids, edges with two equivalent SCaEr4 square pyramids, edges with two equivalent SCa2Er2 tetrahedra, and edges with four SCa2Er3 trigonal bipyramids.