Materials Data on PmMgS3 by Materials Project
MgPmS3 is Ilmenite-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mg2+ is bonded to six S+1.67- atoms to form distorted MgS6 octahedra that share corners with four equivalent PmS6 pentagonal pyramids, edges with three equivalent MgS6 octahedra, and edges with four equivalent PmS6 pentagonal pyramids. There are a spread of Mg–S bond distances ranging from 2.55–2.88 Å. Pm3+ is bonded to six S+1.67- atoms to form distorted PmS6 pentagonal pyramids that share corners with four equivalent MgS6 octahedra, edges with four equivalent MgS6 octahedra, an edgeedge with one PmS6 pentagonal pyramid, and a faceface with one PmS6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 38–48°. There are a spread of Pm–S bond distances ranging from 2.74–2.99 Å. There are two inequivalent S+1.67- sites. In the first S+1.67- site, S+1.67- is bonded in a 4-coordinate geometry to two equivalent Mg2+ and two equivalent Pm3+ atoms. In the second S+1.67- site, S+1.67- is bonded to two equivalent Mg2+ and two equivalent Pm3+ atoms to form edge-sharing SPm2Mg2 trigonal pyramids.