Materials Data on Sm2MgS4 by Materials Project

Abstract

MgSm2S4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to five S2- atoms to form MgS5 square pyramids that share corners with four SmS6 octahedra, edges with four SmS6 octahedra, and edges with four equivalent MgS5 square pyramids. The corner-sharing octahedra tilt angles range from 4–5°. There are a spread of Mg–S bond distances ranging from 2.53–2.66 Å. There are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded to six S2- atoms to form SmS6 octahedra that share corners with three equivalent SmS6 octahedra, corners with two equivalent MgS5 square pyramids, edges with six SmS6 octahedra, and an edgeedge with one MgS5 square pyramid. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of Sm–S bond distances ranging from 2.74–2.89 Å. In the second Sm3+ site, Sm3+ is bonded to six S2- atoms to form SmS6 octahedra that share corners with three equivalent SmS6 octahedra, corners with two equivalent MgS5 square pyramids, edges with four SmS6 octahedra, and edges with three equivalent MgS5 square pyramids. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of Sm–S bond distances ranging from 2.70–2.92 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Mg2+ and two equivalent Sm3+ atoms to form a mixture of corner and edge-sharing SSm2Mg3 square pyramids. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to four Sm3+ atoms. In the third S2- site, S2- is bonded in a 3-coordinate geometry to three Sm3+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Mg2+ and three Sm3+ atoms to form SSm3Mg2 square pyramids that share corners with two equivalent SSm2Mg3 square pyramids and edges with five SSm3Mg2 square pyramids.