CuAgGeSe3 is Stannite-like structured and crystallizes in the monoclinic Cc space group. Ag(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form AgSe4 tetrahedra that share corners with two equivalent Ag(1)Se4 tetrahedra, corners with five equivalent Cu(1)Se4 tetrahedra, and corners with five equivalent Ge(1)Se4 tetrahedra. Cu(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra, corners with five equivalent Ag(1)Se4 tetrahedra, and corners with five equivalent Ge(1)Se4 tetrahedra. Ge(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form GeSe4 tetrahedra that share corners with two equivalent Ge(1)Se4 tetrahedra, corners with five equivalent Ag(1)Se4 tetrahedra, and corners with five equivalent Cu(1)Se4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Ag(1), one Cu(1), and one Ge(1) atom to form SeCuAg2Ge tetrahedra that share corners with two equivalent Se(1)CuAg2Ge tetrahedra, corners with five equivalent Se(2)Cu2AgGe tetrahedra, and corners with five equivalent Se(3)CuAgGe2 tetrahedra. In the second Se site, Se(2) is bonded to one Ag(1), two equivalent Cu(1), and one Ge(1) atom to form SeCu2AgGe tetrahedra that share corners with two equivalent Se(2)Cu2AgGe tetrahedra, corners with five equivalent Se(1)CuAg2Ge tetrahedra, and corners with five equivalent Se(3)CuAgGe2 tetrahedra. In the third Se site, Se(3) is bonded to one Ag(1), one Cu(1), and two equivalent Ge(1) atoms to form SeCuAgGe2 tetrahedra that share corners with two equivalent Se(3)CuAgGe2 tetrahedra, corners with five equivalent Se(2)Cu2AgGe tetrahedra, and corners with five equivalent Se(1)CuAg2Ge tetrahedra.
CuAgGeSe3 is Stannite-like structured and crystallizes in the monoclinic Cc space group. Ag(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form AgSe4 tetrahedra that share corners with two equivalent Ag(1)Se4 tetrahedra, corners with five equivalent Cu(1)Se4 tetrahedra, and corners with five equivalent Ge(1)Se4 tetrahedra. The Ag(1)-Se(2) bond length is 2.62 Å. The Ag(1)-Se(3) bond length is 2.70 Å. Both Ag(1)-Se(1) bond lengths are 2.65 Å. Cu(1) is bonded to one Se(1), one Se(3), and two equivalent Se(2) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra, corners with five equivalent Ag(1)Se4 tetrahedra, and corners with five equivalent Ge(1)Se4 tetrahedra. The Cu(1)-Se(1) bond length is 2.41 Å. The Cu(1)-Se(3) bond length is 2.45 Å. There is one shorter (2.40 Å) and one longer (2.41 Å) Cu(1)-Se(2) bond length. Ge(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form GeSe4 tetrahedra that share corners with two equivalent Ge(1)Se4 tetrahedra, corners with five equivalent Ag(1)Se4 tetrahedra, and corners with five equivalent Cu(1)Se4 tetrahedra. The Ge(1)-Se(1) bond length is 2.37 Å. The Ge(1)-Se(2) bond length is 2.40 Å. There is one shorter (2.50 Å) and one longer (2.55 Å) Ge(1)-Se(3) bond length. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to two equivalent Ag(1), one Cu(1), and one Ge(1) atom to form SeCuAg2Ge tetrahedra that share corners with two equivalent Se(1)CuAg2Ge tetrahedra, corners with five equivalent Se(2)Cu2AgGe tetrahedra, and corners with five equivalent Se(3)CuAgGe2 tetrahedra. In the second Se site, Se(2) is bonded to one Ag(1), two equivalent Cu(1), and one Ge(1) atom to form SeCu2AgGe tetrahedra that share corners with two equivalent Se(2)Cu2AgGe tetrahedra, corners with five equivalent Se(1)CuAg2Ge tetrahedra, and corners with five equivalent Se(3)CuAgGe2 tetrahedra. In the third Se site, Se(3) is bonded to one Ag(1), one Cu(1), and two equivalent Ge(1) atoms to form SeCuAgGe2 tetrahedra that share corners with two equivalent Se(3)CuAgGe2 tetrahedra, corners with five equivalent Se(2)Cu2AgGe tetrahedra, and corners with five equivalent Se(1)CuAg2Ge tetrahedra.