TaCu3(SeS)2 is Sulvanite-derived structured and crystallizes in the orthorhombic Cmm2 space group. Ta(1) is bonded to two equivalent Se(1) and two equivalent S(1) atoms to form distorted TaSe2S2 tetrahedra that share edges with two equivalent Cu(2)Se2S2 tetrahedra and edges with four equivalent Cu(1)Se2S2 tetrahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Se(1) and two equivalent S(1) atoms to form distorted CuSe2S2 tetrahedra that share corners with four equivalent Cu(1)Se2S2 tetrahedra, corners with four equivalent Cu(2)Se2S2 tetrahedra, and edges with two equivalent Ta(1)Se2S2 tetrahedra. In the second Cu site, Cu(2) is bonded to two equivalent Se(1) and two equivalent S(1) atoms to form distorted CuSe2S2 tetrahedra that share corners with eight equivalent Cu(1)Se2S2 tetrahedra and edges with two equivalent Ta(1)Se2S2 tetrahedra. Se(1) is bonded to one Ta(1), one Cu(2), and two equivalent Cu(1) atoms to form SeTaCu3 tetrahedra that share corners with two equivalent Se(1)TaCu3 tetrahedra, corners with four equivalent S(1)TaCu3 tetrahedra,  an edgeedge with one Se(1)TaCu3 tetrahedra, and edges with two equivalent S(1)TaCu3 tetrahedra. S(1) is bonded to one Ta(1), one Cu(2), and two equivalent Cu(1) atoms to form distorted STaCu3 tetrahedra that share corners with two equivalent S(1)TaCu3 tetrahedra, corners with four equivalent Se(1)TaCu3 tetrahedra,  an edgeedge with one S(1)TaCu3 tetrahedra, and edges with two equivalent Se(1)TaCu3 tetrahedra.
TaCu3(SeS)2 is Sulvanite-derived structured and crystallizes in the orthorhombic Cmm2 space group. Ta(1) is bonded to two equivalent Se(1) and two equivalent S(1) atoms to form distorted TaSe2S2 tetrahedra that share edges with two equivalent Cu(2)Se2S2 tetrahedra and edges with four equivalent Cu(1)Se2S2 tetrahedra. Both Ta(1)-Se(1) bond lengths are 2.44 Å. Both Ta(1)-S(1) bond lengths are 2.31 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent Se(1) and two equivalent S(1) atoms to form distorted CuSe2S2 tetrahedra that share corners with four equivalent Cu(1)Se2S2 tetrahedra, corners with four equivalent Cu(2)Se2S2 tetrahedra, and edges with two equivalent Ta(1)Se2S2 tetrahedra. Both Cu(1)-Se(1) bond lengths are 2.48 Å. Both Cu(1)-S(1) bond lengths are 2.33 Å. In the second Cu site, Cu(2) is bonded to two equivalent Se(1) and two equivalent S(1) atoms to form distorted CuSe2S2 tetrahedra that share corners with eight equivalent Cu(1)Se2S2 tetrahedra and edges with two equivalent Ta(1)Se2S2 tetrahedra. Both Cu(2)-Se(1) bond lengths are 2.46 Å. Both Cu(2)-S(1) bond lengths are 2.34 Å. Se(1) is bonded to one Ta(1), one Cu(2), and two equivalent Cu(1) atoms to form SeTaCu3 tetrahedra that share corners with two equivalent Se(1)TaCu3 tetrahedra, corners with four equivalent S(1)TaCu3 tetrahedra,  an edgeedge with one Se(1)TaCu3 tetrahedra, and edges with two equivalent S(1)TaCu3 tetrahedra. S(1) is bonded to one Ta(1), one Cu(2), and two equivalent Cu(1) atoms to form distorted STaCu3 tetrahedra that share corners with two equivalent S(1)TaCu3 tetrahedra, corners with four equivalent Se(1)TaCu3 tetrahedra,  an edgeedge with one S(1)TaCu3 tetrahedra, and edges with two equivalent Se(1)TaCu3 tetrahedra.