DOI: 10.17188/1197128
title: Materials Data on Er2CrS4 by Materials Project

description: CrEr2S4 crystallizes in the orthorhombic Pca2_1 space group. The structure is three-dimensional. there are four inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share a cornercorner with one CrS6 octahedra, corners with two equivalent ErS6 octahedra, corners with four ErS7 pentagonal bipyramids, an edgeedge with one ErS6 octahedra, edges with four CrS6 octahedra, and edges with three ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 11–53°. There are a spread of Er–S bond distances ranging from 2.65–2.72 Å. In the second Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share a cornercorner with one CrS6 octahedra, corners with two equivalent ErS6 octahedra, corners with four ErS7 pentagonal bipyramids, an edgeedge with one ErS6 octahedra, edges with four CrS6 octahedra, and edges with three ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 11–53°. There are a spread of Er–S bond distances ranging from 2.64–2.74 Å. In the third Er3+ site, Er3+ is bonded to seven S2- atoms to form distorted ErS7 pentagonal bipyramids that share corners with four ErS6 octahedra, corners with four CrS6 octahedra, edges with three ErS6 octahedra, edges with three CrS6 octahedra, and faces with two equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 15–71°. There are a spread of Er–S bond distances ranging from 2.71–2.98 Å. In the fourth Er3+ site, Er3+ is bonded to seven S2- atoms to form distorted ErS7 pentagonal bipyramids that share corners with four ErS6 octahedra, corners with four CrS6 octahedra, edges with three ErS6 octahedra, edges with three CrS6 octahedra, and faces with two equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 16–70°. There are a spread of Er–S bond distances ranging from 2.70–2.98 Å. There are two inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded to six S2- atoms to form CrS6 octahedra that share a cornercorner with one ErS6 octahedra, corners with two equivalent CrS6 octahedra, corners with four ErS7 pentagonal bipyramids, an edgeedge with one CrS6 octahedra, edges with four ErS6 octahedra, and edges with three ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 10–53°. There are a spread of Cr–S bond distances ranging from 2.42–2.74 Å. In the second Cr2+ site, Cr2+ is bonded to six S2- atoms to form CrS6 octahedra that share a cornercorner with one ErS6 octahedra, corners with two equivalent CrS6 octahedra, corners with four ErS7 pentagonal bipyramids, an edgeedge with one CrS6 octahedra, edges with four ErS6 octahedra, and edges with three ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 10–53°. There are a spread of Cr–S bond distances ranging from 2.43–2.86 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to three Er3+ and two Cr2+ atoms to form distorted SEr3Cr2 square pyramids that share a cornercorner with one SEr3Cr tetrahedra, corners with eight SEr3Cr2 trigonal bipyramids, edges with four SEr3Cr2 square pyramids, an edgeedge with one SEr3Cr tetrahedra, and edges with two SEr3Cr2 trigonal bipyramids. In the second S2- site, S2- is bonded to three Er3+ and two Cr2+ atoms to form SEr3Cr2 square pyramids that share corners with two equivalent SEr4Cr square pyramids, a cornercorner with one SEr3Cr tetrahedra, corners with six SEr3Cr2 trigonal bipyramids, edges with three SEr3Cr2 square pyramids, an edgeedge with one SEr3Cr tetrahedra, and edges with three SEr4Cr trigonal bipyramids. In the third S2- site, S2- is bonded to four Er3+ and one Cr2+ atom to form SEr4Cr square pyramids that share corners with two equivalent SEr3Cr2 square pyramids, corners with two equivalent SEr3Cr tetrahedra, corners with two equivalent SEr4Cr trigonal bipyramids, edges with three SEr3Cr2 square pyramids, an edgeedge with one SEr3Cr tetrahedra, and edges with five SEr3Cr2 trigonal bipyramids. In the fourth S2- site, S2- is bonded to three Er3+ and two Cr2+ atoms to form distorted SEr3Cr2 trigonal bipyramids that share corners with six SEr3Cr2 square pyramids, corners with two equivalent SEr3Cr tetrahedra, corners with two equivalent SEr3Cr2 trigonal bipyramids, edges with three SEr3Cr2 square pyramids, an edgeedge with one SEr3Cr tetrahedra, and edges with three SEr4Cr trigonal bipyramids. In the fifth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Er3+ and one Cr2+ atom. In the sixth S2- site, S2- is bonded to four Er3+ and one Cr2+ atom to form distorted SEr4Cr trigonal bipyramids that share corners with eight SEr3Cr2 square pyramids, corners with three equivalent SEr3Cr tetrahedra, edges with two SEr3Cr2 square pyramids, and edges with four SEr3Cr2 trigonal bipyramids. In the seventh S2- site, S2- is bonded to three Er3+ and one Cr2+ atom to form a mixture of distorted edge and corner-sharing SEr3Cr tetrahedra. In the eighth S2- site, S2- is bonded to three Er3+ and two Cr2+ atoms to form distorted SEr3Cr2 trigonal bipyramids that share corners with two equivalent SEr3Cr2 square pyramids, corners with three equivalent SEr3Cr tetrahedra, corners with two equivalent SEr3Cr2 trigonal bipyramids, edges with five SEr3Cr2 square pyramids, and edges with three SEr3Cr2 trigonal bipyramids.