Materials Data on Mg2GeS4 by Materials Project

Mg2GeS4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share corners with four equivalent MgS6 octahedra, corners with two equivalent GeS4 tetrahedra, edges with four MgS6 octahedra, and edges with two equivalent GeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Mg–S bond distances ranging from 2.59–2.64 Å. In the second Mg2+ site, Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share corners with eight MgS6 octahedra, corners with four equivalent GeS4 tetrahedra, edges with two equivalent MgS6 octahedra, and an edgeedge with one GeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–57°. There are a spread of Mg–S bond distances ranging from 2.58–2.67 Å. Ge4+ is bonded to four S2- atoms to form GeS4 tetrahedra that share corners with six MgS6 octahedra and edges with three MgS6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There are one shorter (2.21 Å) and three longer (2.25 Å) Ge–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Ge4+ atom. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Mg2+ and one Ge4+ atom. In the third S2- site, S2- is bonded to three Mg2+ and one Ge4+ atom to form distorted corner-sharing SMg3Ge trigonal pyramids.