Materials Data on K4GeS4 by Materials Project
K4GeS4 crystallizes in the cubic P-43n space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six S2- atoms to form distorted KS6 octahedra that share corners with six KS6 octahedra, corners with three GeS4 tetrahedra, edges with twelve KS6 octahedra, and a faceface with one GeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–26°. There are a spread of K–S bond distances ranging from 3.21–3.42 Å. In the second K1+ site, K1+ is bonded to six S2- atoms to form distorted KS6 octahedra that share corners with six equivalent KS6 octahedra, corners with three equivalent GeS4 tetrahedra, edges with twelve KS6 octahedra, and a faceface with one GeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 21–22°. There are three shorter (3.31 Å) and three longer (3.40 Å) K–S bond lengths. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four equivalent S2- atoms to form GeS4 tetrahedra that share corners with twelve KS6 octahedra and faces with four equivalent KS6 octahedra. The corner-sharing octahedra tilt angles range from 45–52°. All Ge–S bond lengths are 2.25 Å. In the second Ge4+ site, Ge4+ is bonded to four equivalent S2- atoms to form GeS4 tetrahedra that share corners with twelve equivalent KS6 octahedra and faces with four equivalent KS6 octahedra. The corner-sharing octahedral tilt angles are 52°. All Ge–S bond lengths are 2.24 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 7-coordinate geometry to six K1+ and one Ge4+ atom. In the second S2- site, S2- is bonded in a 7-coordinate geometry to six K1+ and one Ge4+ atom.