KCu3GeSe4 crystallizes in the cubic P-43m space group. K(1) is bonded to four equivalent Se(1) atoms to form KSe4 tetrahedra that share corners with four equivalent Ge(1)Se4 tetrahedra and corners with twelve equivalent Cu(1)Se4 tetrahedra. Cu(1) is bonded to four equivalent Se(1) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent K(1)Se4 tetrahedra, corners with eight equivalent Cu(1)Se4 tetrahedra, and edges with two equivalent Ge(1)Se4 tetrahedra. Ge(1) is bonded to four equivalent Se(1) atoms to form GeSe4 tetrahedra that share corners with four equivalent K(1)Se4 tetrahedra and edges with six equivalent Cu(1)Se4 tetrahedra. Se(1) is bonded to one K(1), three equivalent Cu(1), and one Ge(1) atom to form a mixture of distorted edge and corner-sharing SeKCu3Ge trigonal bipyramids.
KCu3GeSe4 crystallizes in the cubic P-43m space group. K(1) is bonded to four equivalent Se(1) atoms to form KSe4 tetrahedra that share corners with four equivalent Ge(1)Se4 tetrahedra and corners with twelve equivalent Cu(1)Se4 tetrahedra. All K(1)-Se(1) bond lengths are 3.02 Å. Cu(1) is bonded to four equivalent Se(1) atoms to form distorted CuSe4 tetrahedra that share corners with four equivalent K(1)Se4 tetrahedra, corners with eight equivalent Cu(1)Se4 tetrahedra, and edges with two equivalent Ge(1)Se4 tetrahedra. All Cu(1)-Se(1) bond lengths are 2.59 Å. Ge(1) is bonded to four equivalent Se(1) atoms to form GeSe4 tetrahedra that share corners with four equivalent K(1)Se4 tetrahedra and edges with six equivalent Cu(1)Se4 tetrahedra. All Ge(1)-Se(1) bond lengths are 2.35 Å. Se(1) is bonded to one K(1), three equivalent Cu(1), and one Ge(1) atom to form a mixture of distorted edge and corner-sharing SeKCu3Ge trigonal bipyramids.