DOI: 10.17188/1652232
title: Materials Data on Pm2MgS4 by Materials Project

description: MgPm2S4 is Aluminum carbonitride-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four S2- atoms to form MgS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent PmS6 octahedra, and corners with nine PmS5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 62–66°. There are a spread of Mg–S bond distances ranging from 2.40–2.51 Å. In the second Mg2+ site, Mg2+ is bonded to six S2- atoms to form distorted MgS6 octahedra that share a cornercorner with one MgS4 tetrahedra, corners with five PmS5 trigonal bipyramids, edges with two equivalent MgS6 octahedra, and edges with four equivalent PmS6 octahedra. There are a spread of Mg–S bond distances ranging from 2.72–3.04 Å. There are four inequivalent Pm3+ sites. In the first Pm3+ site, Pm3+ is bonded to five S2- atoms to form distorted PmS5 trigonal bipyramids that share a cornercorner with one PmS6 octahedra, corners with two equivalent MgS6 octahedra, corners with three equivalent MgS4 tetrahedra, corners with four PmS5 trigonal bipyramids, and edges with two PmS5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 62–64°. There are a spread of Pm–S bond distances ranging from 2.64–3.07 Å. In the second Pm3+ site, Pm3+ is bonded to six S2- atoms to form distorted PmS6 octahedra that share corners with two equivalent MgS4 tetrahedra, corners with four PmS5 trigonal bipyramids, edges with two equivalent PmS6 octahedra, and edges with four equivalent MgS6 octahedra. There are a spread of Pm–S bond distances ranging from 2.86–2.92 Å. In the third Pm3+ site, Pm3+ is bonded to five S2- atoms to form distorted PmS5 trigonal bipyramids that share a cornercorner with one PmS6 octahedra, corners with two equivalent MgS6 octahedra, corners with three equivalent MgS4 tetrahedra, corners with four PmS5 trigonal bipyramids, and edges with two PmS5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 58–67°. There are a spread of Pm–S bond distances ranging from 2.64–3.09 Å. In the fourth Pm3+ site, Pm3+ is bonded to five S2- atoms to form distorted PmS5 trigonal bipyramids that share a cornercorner with one MgS6 octahedra, corners with two equivalent PmS6 octahedra, corners with three equivalent MgS4 tetrahedra, corners with four PmS5 trigonal bipyramids, and edges with two PmS5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 61–64°. There are a spread of Pm–S bond distances ranging from 2.63–3.06 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Mg2+ and two Pm3+ atoms to form a mixture of distorted edge and corner-sharing SPm2Mg2 tetrahedra. In the second S2- site, S2- is bonded to two Mg2+ and two equivalent Pm3+ atoms to form distorted SPm2Mg2 tetrahedra that share corners with twelve SPm2Mg2 tetrahedra and edges with three SPm3Mg tetrahedra. In the third S2- site, S2- is bonded to one Mg2+ and three Pm3+ atoms to form distorted SPm3Mg tetrahedra that share corners with eight SPm2Mg2 tetrahedra and edges with two SPm3Mg tetrahedra. In the fourth S2- site, S2- is bonded in a trigonal planar geometry to three Pm3+ atoms. In the fifth S2- site, S2- is bonded to one Mg2+ and three Pm3+ atoms to form distorted SPm3Mg tetrahedra that share corners with eight SPm2Mg2 tetrahedra and edges with two SPm3Mg tetrahedra. In the sixth S2- site, S2- is bonded to one Mg2+ and three Pm3+ atoms to form distorted SPm3Mg tetrahedra that share corners with eight SPm2Mg2 tetrahedra and edges with two SPm3Mg tetrahedra. In the seventh S2- site, S2- is bonded to one Mg2+ and three Pm3+ atoms to form distorted SPm3Mg tetrahedra that share corners with twelve SPm2Mg2 tetrahedra and edges with three SPm3Mg tetrahedra. In the eighth S2- site, S2- is bonded to two equivalent Mg2+ and two Pm3+ atoms to form SPm2Mg2 tetrahedra that share corners with twelve SPm2Mg2 tetrahedra and edges with three SPm3Mg tetrahedra.