Materials Data on Fe2GeS4 by Materials Project

Fe2GeS4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with four equivalent FeS6 octahedra, corners with two equivalent GeS4 tetrahedra, edges with four FeS6 octahedra, and edges with two equivalent GeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–50°. There are a spread of Fe–S bond distances ranging from 2.20–2.38 Å. In the second Fe2+ site, Fe2+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with eight FeS6 octahedra, corners with four equivalent GeS4 tetrahedra, edges with two equivalent FeS6 octahedra, and an edgeedge with one GeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–50°. There are a spread of Fe–S bond distances ranging from 2.22–2.51 Å. Ge4+ is bonded to four S2- atoms to form distorted GeS4 tetrahedra that share corners with six FeS6 octahedra and edges with three FeS6 octahedra. The corner-sharing octahedra tilt angles range from 67–69°. There are three shorter (2.26 Å) and one longer (2.27 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 Fe2+ and one Ge4+ atom. In the second S2- site, S2- is bonded to three Fe2+ and one Ge4+ atom to form corner-sharing SFe3Ge tetrahedra. In the third S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Fe2+ and one Ge4+ atom.