Materials Data on ErMgS3 by Materials Project
MgErS3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mg2+ is bonded to six S+1.67- atoms to form MgS6 octahedra that share corners with eight equivalent ErS4 tetrahedra and edges with three equivalent MgS6 octahedra. There are a spread of Mg–S bond distances ranging from 2.58–2.70 Å. Er3+ is bonded to four S+1.67- atoms to form ErS4 tetrahedra that share corners with eight equivalent MgS6 octahedra and an edgeedge with one ErS4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–76°. There are two shorter (2.58 Å) and two longer (2.62 Å) Er–S bond lengths. There are two inequivalent S+1.67- sites. In the first S+1.67- site, S+1.67- is bonded in a distorted trigonal planar geometry to two equivalent Mg2+ and one Er3+ atom. In the second S+1.67- site, S+1.67- is bonded to two equivalent Mg2+ and two equivalent Er3+ atoms to form distorted edge-sharing SEr2Mg2 trigonal pyramids.