Materials Data on FeCu6GeS8 by Materials Project

FeCu6GeS8 is Stannite-like structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Fe3+ is bonded to four equivalent S2- atoms to form FeS4 tetrahedra that share corners with twelve equivalent CuS4 tetrahedra. All Fe–S bond lengths are 2.20 Å. Cu+1.50+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with two equivalent FeS4 tetrahedra, corners with two equivalent GeS4 tetrahedra, and corners with eight equivalent CuS4 tetrahedra. There are two shorter (2.26 Å) and two longer (2.30 Å) Cu–S bond lengths. Ge4+ is bonded to four equivalent S2- atoms to form GeS4 tetrahedra that share corners with twelve equivalent CuS4 tetrahedra. All Ge–S bond lengths are 2.27 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Cu+1.50+ and one Ge4+ atom to form corner-sharing SCu3Ge tetrahedra. In the second S2- site, S2- is bonded to one Fe3+ and three equivalent Cu+1.50+ atoms to form corner-sharing SFeCu3 tetrahedra.