Cu2GeSe3 is Chalcopyrite-like structured and crystallizes in the orthorhombic Imm2 space group. Cu(1) is bonded to one Se(2) and three equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with five equivalent Ge(1)Se4 tetrahedra and corners with seven equivalent Cu(1)Se4 tetrahedra. Ge(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form GeSe4 tetrahedra that share corners with two equivalent Ge(1)Se4 tetrahedra and corners with ten equivalent Cu(1)Se4 tetrahedra. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded to two equivalent Cu(1) and two equivalent Ge(1) atoms to form SeCu2Ge2 tetrahedra that share corners with two equivalent Se(2)Cu2Ge2 tetrahedra and corners with ten equivalent Se(1)Cu3Ge tetrahedra. In the second Se site, Se(1) is bonded to three equivalent Cu(1) and one Ge(1) atom to form SeCu3Ge tetrahedra that share corners with five equivalent Se(2)Cu2Ge2 tetrahedra and corners with seven equivalent Se(1)Cu3Ge tetrahedra.
Cu2GeSe3 is Chalcopyrite-like structured and crystallizes in the orthorhombic Imm2 space group. Cu(1) is bonded to one Se(2) and three equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with five equivalent Ge(1)Se4 tetrahedra and corners with seven equivalent Cu(1)Se4 tetrahedra. The Cu(1)-Se(2) bond length is 2.41 Å. There are two shorter (2.39 Å) and one longer (2.40 Å) Cu(1)-Se(1) bond length. Ge(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form GeSe4 tetrahedra that share corners with two equivalent Ge(1)Se4 tetrahedra and corners with ten equivalent Cu(1)Se4 tetrahedra. Both Ge(1)-Se(1) bond lengths are 2.38 Å. Both Ge(1)-Se(2) bond lengths are 2.50 Å. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded to two equivalent Cu(1) and two equivalent Ge(1) atoms to form SeCu2Ge2 tetrahedra that share corners with two equivalent Se(2)Cu2Ge2 tetrahedra and corners with ten equivalent Se(1)Cu3Ge tetrahedra. In the second Se site, Se(1) is bonded to three equivalent Cu(1) and one Ge(1) atom to form SeCu3Ge tetrahedra that share corners with five equivalent Se(2)Cu2Ge2 tetrahedra and corners with seven equivalent Se(1)Cu3Ge tetrahedra.