TaCu3(TeSe)2 is Sulvanite-derived structured and crystallizes in the orthorhombic Cmm2 space group. Ta(1) is bonded in a 10-coordinate geometry to two equivalent Cu(2), four equivalent Cu(1), two equivalent Te(1), and two equivalent Se(1) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to two equivalent Ta(1), two equivalent Te(1), and two equivalent Se(1) atoms. In the second Cu site, Cu(2) is bonded in a 6-coordinate geometry to two equivalent Ta(1), two equivalent Te(1), and two equivalent Se(1) atoms. Te(1) is bonded to one Ta(1), one Cu(2), and two equivalent Cu(1) atoms to form TeTaCu3 tetrahedra that share corners with two equivalent Te(1)TaCu3 tetrahedra, corners with four equivalent Se(1)TaCu3 tetrahedra,  an edgeedge with one Te(1)TaCu3 tetrahedra, and edges with two equivalent Se(1)TaCu3 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 Te(1)TaCu3 tetrahedra,  an edgeedge with one Se(1)TaCu3 tetrahedra, and edges with two equivalent Te(1)TaCu3 tetrahedra.
TaCu3(TeSe)2 is Sulvanite-derived structured and crystallizes in the orthorhombic Cmm2 space group. Ta(1) is bonded in a 10-coordinate geometry to two equivalent Cu(2), four equivalent Cu(1), two equivalent Te(1), and two equivalent Se(1) atoms. There is one shorter (2.88 Å) and one longer (2.99 Å) Ta(1)-Cu(2) bond length. All Ta(1)-Cu(1) bond lengths are 2.94 Å. Both Ta(1)-Te(1) bond lengths are 2.67 Å. Both Ta(1)-Se(1) bond lengths are 2.47 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 6-coordinate geometry to two equivalent Ta(1), two equivalent Te(1), and two equivalent Se(1) atoms. Both Cu(1)-Te(1) bond lengths are 2.62 Å. Both Cu(1)-Se(1) bond lengths are 2.49 Å. In the second Cu site, Cu(2) is bonded in a 6-coordinate geometry to two equivalent Ta(1), two equivalent Te(1), and two equivalent Se(1) atoms. Both Cu(2)-Te(1) bond lengths are 2.61 Å. Both Cu(2)-Se(1) bond lengths are 2.50 Å. Te(1) is bonded to one Ta(1), one Cu(2), and two equivalent Cu(1) atoms to form TeTaCu3 tetrahedra that share corners with two equivalent Te(1)TaCu3 tetrahedra, corners with four equivalent Se(1)TaCu3 tetrahedra,  an edgeedge with one Te(1)TaCu3 tetrahedra, and edges with two equivalent Se(1)TaCu3 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 Te(1)TaCu3 tetrahedra,  an edgeedge with one Se(1)TaCu3 tetrahedra, and edges with two equivalent Te(1)TaCu3 tetrahedra.