NbCu3(TeSe)2 is Sulvanite-derived structured and crystallizes in the orthorhombic Cmm2 space group. Nb(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 Nb(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 Nb(1), two equivalent Te(1), and two equivalent Se(1) atoms. Te(1) is bonded to one Nb(1), one Cu(2), and two equivalent Cu(1) atoms to form TeNbCu3 tetrahedra that share corners with two equivalent Te(1)NbCu3 tetrahedra, corners with four equivalent Se(1)NbCu3 tetrahedra,  an edgeedge with one Te(1)NbCu3 tetrahedra, and edges with two equivalent Se(1)NbCu3 tetrahedra. Se(1) is bonded to one Nb(1), one Cu(2), and two equivalent Cu(1) atoms to form SeNbCu3 tetrahedra that share corners with two equivalent Se(1)NbCu3 tetrahedra, corners with four equivalent Te(1)NbCu3 tetrahedra,  an edgeedge with one Se(1)NbCu3 tetrahedra, and edges with two equivalent Te(1)NbCu3 tetrahedra.
NbCu3(TeSe)2 is Sulvanite-derived structured and crystallizes in the orthorhombic Cmm2 space group. Nb(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 (2.87 Å) and one longer (2.97 Å) Nb(1)-Cu(2) bond length. All Nb(1)-Cu(1) bond lengths are 2.93 Å. Both Nb(1)-Te(1) bond lengths are 2.67 Å. Both Nb(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 Nb(1), two equivalent Te(1), and two equivalent Se(1) atoms. Both Cu(1)-Te(1) bond lengths are 2.63 Å. Both Cu(1)-Se(1) bond lengths are 2.47 Å. In the second Cu site, Cu(2) is bonded in a 6-coordinate geometry to two equivalent Nb(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 2.48 Å. Te(1) is bonded to one Nb(1), one Cu(2), and two equivalent Cu(1) atoms to form TeNbCu3 tetrahedra that share corners with two equivalent Te(1)NbCu3 tetrahedra, corners with four equivalent Se(1)NbCu3 tetrahedra,  an edgeedge with one Te(1)NbCu3 tetrahedra, and edges with two equivalent Se(1)NbCu3 tetrahedra. Se(1) is bonded to one Nb(1), one Cu(2), and two equivalent Cu(1) atoms to form SeNbCu3 tetrahedra that share corners with two equivalent Se(1)NbCu3 tetrahedra, corners with four equivalent Te(1)NbCu3 tetrahedra,  an edgeedge with one Se(1)NbCu3 tetrahedra, and edges with two equivalent Te(1)NbCu3 tetrahedra.