Materials Data on Tm2MgS4 by Materials Project

MgTm2S4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to four S2- atoms to form MgS4 tetrahedra that share corners with six TmS6 octahedra and edges with three TmS6 octahedra. The corner-sharing octahedra tilt angles range from 59–67°. There are a spread of Mg–S bond distances ranging from 2.39–2.47 Å. There are two inequivalent Tm3+ sites. In the first Tm3+ site, Tm3+ is bonded to six S2- atoms to form TmS6 octahedra that share corners with four equivalent TmS6 octahedra, corners with two equivalent MgS4 tetrahedra, edges with four TmS6 octahedra, and edges with two equivalent MgS4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of Tm–S bond distances ranging from 2.66–2.74 Å. In the second Tm3+ site, Tm3+ is bonded to six S2- atoms to form TmS6 octahedra that share corners with eight TmS6 octahedra, corners with four equivalent MgS4 tetrahedra, edges with two equivalent TmS6 octahedra, and an edgeedge with one MgS4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–54°. There are a spread of Tm–S bond distances ranging from 2.69–2.77 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Tm3+ atoms. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Tm3+ atoms. In the third S2- site, S2- is bonded to one Mg2+ and three Tm3+ atoms to form distorted corner-sharing STm3Mg trigonal pyramids.