Materials Data on CoCu2GeSe4 by Materials Project

Cu2CoGeSe4 is Stannite-like structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Co2+ is bonded to four Se2- atoms to form CoSe4 tetrahedra that share corners with four equivalent GeSe4 tetrahedra and corners with eight CuSe4 tetrahedra. All Co–Se bond lengths are 2.38 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent CoSe4 tetrahedra, corners with four equivalent CuSe4 tetrahedra, and corners with four equivalent GeSe4 tetrahedra. All Cu–Se bond lengths are 2.42 Å. In the second Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent CoSe4 tetrahedra, corners with four equivalent CuSe4 tetrahedra, and corners with four equivalent GeSe4 tetrahedra. All Cu–Se bond lengths are 2.43 Å. Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share corners with four equivalent CoSe4 tetrahedra and corners with eight CuSe4 tetrahedra. All Ge–Se bond lengths are 2.47 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Co2+, two Cu1+, and one Ge4+ atom to form corner-sharing SeCoCu2Ge tetrahedra. In the second Se2- site, Se2- is bonded to one Co2+, two Cu1+, and one Ge4+ atom to form corner-sharing SeCoCu2Ge tetrahedra.