Cu2CdGeSe4 is Stannite-like structured and crystallizes in the monoclinic Pc space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form CuSe4 tetrahedra that share corners with four equivalent Cu(2)Se4 tetrahedra, corners with four equivalent Cd(1)Se4 tetrahedra, and corners with four equivalent Ge(1)Se4 tetrahedra. In the second Cu site, Cu(2) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form CuSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cd(1)Se4 tetrahedra, and corners with four equivalent Ge(1)Se4 tetrahedra. Cd(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form CdSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and corners with four equivalent Ge(1)Se4 tetrahedra. Ge(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form GeSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and corners with four equivalent Cd(1)Se4 tetrahedra. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cu(1), one Cu(2), one Cd(1), and one Ge(1) atom to form corner-sharing SeCdCu2Ge tetrahedra. In the second Se site, Se(2) is bonded to one Cu(1), one Cu(2), one Cd(1), and one Ge(1) atom to form corner-sharing SeCdCu2Ge tetrahedra. In the third Se site, Se(3) is bonded to one Cu(1), one Cu(2), one Cd(1), and one Ge(1) atom to form corner-sharing SeCdCu2Ge tetrahedra. In the fourth Se site, Se(4) is bonded to one Cu(1), one Cu(2), one Cd(1), and one Ge(1) atom to form corner-sharing SeCdCu2Ge tetrahedra.
Cu2CdGeSe4 is Stannite-like structured and crystallizes in the monoclinic Pc space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form CuSe4 tetrahedra that share corners with four equivalent Cu(2)Se4 tetrahedra, corners with four equivalent Cd(1)Se4 tetrahedra, and corners with four equivalent Ge(1)Se4 tetrahedra. The Cu(1)-Se(1) bond length is 2.42 Å. The Cu(1)-Se(2) bond length is 2.40 Å. The Cu(1)-Se(3) bond length is 2.42 Å. The Cu(1)-Se(4) bond length is 2.43 Å. In the second Cu site, Cu(2) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form CuSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cd(1)Se4 tetrahedra, and corners with four equivalent Ge(1)Se4 tetrahedra. The Cu(2)-Se(1) bond length is 2.45 Å. The Cu(2)-Se(2) bond length is 2.47 Å. The Cu(2)-Se(3) bond length is 2.42 Å. The Cu(2)-Se(4) bond length is 2.44 Å. Cd(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form CdSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and corners with four equivalent Ge(1)Se4 tetrahedra. The Cd(1)-Se(1) bond length is 2.68 Å. The Cd(1)-Se(2) bond length is 2.69 Å. The Cd(1)-Se(3) bond length is 2.66 Å. The Cd(1)-Se(4) bond length is 2.67 Å. Ge(1) is bonded to one Se(1), one Se(2), one Se(3), and one Se(4) atom to form GeSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and corners with four equivalent Cd(1)Se4 tetrahedra. The Ge(1)-Se(1) bond length is 2.45 Å. The Ge(1)-Se(2) bond length is 2.45 Å. The Ge(1)-Se(3) bond length is 2.44 Å. The Ge(1)-Se(4) bond length is 2.42 Å. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cu(1), one Cu(2), one Cd(1), and one Ge(1) atom to form corner-sharing SeCdCu2Ge tetrahedra. In the second Se site, Se(2) is bonded to one Cu(1), one Cu(2), one Cd(1), and one Ge(1) atom to form corner-sharing SeCdCu2Ge tetrahedra. In the third Se site, Se(3) is bonded to one Cu(1), one Cu(2), one Cd(1), and one Ge(1) atom to form corner-sharing SeCdCu2Ge tetrahedra. In the fourth Se site, Se(4) is bonded to one Cu(1), one Cu(2), one Cd(1), and one Ge(1) atom to form corner-sharing SeCdCu2Ge tetrahedra.