Ti8Cu3S16 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one S(4), one S(5), two equivalent S(1), and two equivalent S(3) atoms to form TiS6 octahedra that share corners with four equivalent Cu(1)S6 octahedra, edges with two equivalent Ti(3)S6 octahedra, edges with four equivalent Ti(2)S6 octahedra, and  a faceface with one Cu(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. In the second Ti site, Ti(2) is bonded to one S(1), one S(3), one S(4), one S(5), and two equivalent S(2) atoms to form TiS6 octahedra that share corners with two equivalent Cu(1)S6 octahedra, corners with two equivalent Cu(2)S6 octahedra, edges with two equivalent Ti(1)S6 octahedra, edges with two equivalent Ti(2)S6 octahedra, edges with two equivalent Ti(3)S6 octahedra, and  a faceface with one Cu(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. In the third Ti site, Ti(3) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form TiS6 octahedra that share corners with two equivalent Cu(2)S6 octahedra, corners with four equivalent Cu(1)S6 octahedra, edges with two equivalent Ti(1)S6 octahedra, and edges with four equivalent Ti(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 46-48°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form CuS6 octahedra that share corners with four equivalent Ti(1)S6 octahedra, corners with four equivalent Ti(2)S6 octahedra, corners with four equivalent Ti(3)S6 octahedra,  an edgeedge with one Cu(1)S6 octahedra, and faces with two equivalent Ti(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 46-48°. In the second Cu site, Cu(2) is bonded to two equivalent S(5) and four equivalent S(1) atoms to form CuS6 octahedra that share corners with four equivalent Ti(3)S6 octahedra, corners with eight equivalent Ti(2)S6 octahedra, and faces with two equivalent Ti(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. There are five inequivalent S sites. In the first S site, S(5) is bonded in a rectangular see-saw-like geometry to one Ti(1), two equivalent Ti(2), and one Cu(2) atom. In the second S site, S(1) is bonded in a rectangular see-saw-like geometry to one Ti(1), one Ti(2), one Ti(3), and one Cu(2) atom. In the third S site, S(2) is bonded in a rectangular see-saw-like geometry to one Ti(3), two equivalent Ti(2), and one Cu(1) atom. In the fourth S site, S(3) is bonded in a rectangular see-saw-like geometry to one Ti(1), one Ti(2), one Ti(3), and one Cu(1) atom. In the fifth S site, S(4) is bonded to one Ti(1), two equivalent Ti(2), and two equivalent Cu(1) atoms to form distorted edge-sharing STi3Cu2 square pyramids.
Ti8Cu3S16 crystallizes in the monoclinic C2/m space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one S(4), one S(5), two equivalent S(1), and two equivalent S(3) atoms to form TiS6 octahedra that share corners with four equivalent Cu(1)S6 octahedra, edges with two equivalent Ti(3)S6 octahedra, edges with four equivalent Ti(2)S6 octahedra, and  a faceface with one Cu(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. The Ti(1)-S(4) bond length is 2.45 Å. The Ti(1)-S(5) bond length is 2.46 Å. Both Ti(1)-S(1) bond lengths are 2.47 Å. Both Ti(1)-S(3) bond lengths are 2.41 Å. In the second Ti site, Ti(2) is bonded to one S(1), one S(3), one S(4), one S(5), and two equivalent S(2) atoms to form TiS6 octahedra that share corners with two equivalent Cu(1)S6 octahedra, corners with two equivalent Cu(2)S6 octahedra, edges with two equivalent Ti(1)S6 octahedra, edges with two equivalent Ti(2)S6 octahedra, edges with two equivalent Ti(3)S6 octahedra, and  a faceface with one Cu(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. The Ti(2)-S(1) bond length is 2.42 Å. The Ti(2)-S(3) bond length is 2.46 Å. The Ti(2)-S(4) bond length is 2.48 Å. The Ti(2)-S(5) bond length is 2.43 Å. There is one shorter (2.41 Å) and one longer (2.47 Å) Ti(2)-S(2) bond length. In the third Ti site, Ti(3) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form TiS6 octahedra that share corners with two equivalent Cu(2)S6 octahedra, corners with four equivalent Cu(1)S6 octahedra, edges with two equivalent Ti(1)S6 octahedra, and edges with four equivalent Ti(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 46-48°. Both Ti(3)-S(1) bond lengths are 2.43 Å. Both Ti(3)-S(2) bond lengths are 2.44 Å. Both Ti(3)-S(3) bond lengths are 2.44 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form CuS6 octahedra that share corners with four equivalent Ti(1)S6 octahedra, corners with four equivalent Ti(2)S6 octahedra, corners with four equivalent Ti(3)S6 octahedra,  an edgeedge with one Cu(1)S6 octahedra, and faces with two equivalent Ti(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 46-48°. Both Cu(1)-S(2) bond lengths are 2.43 Å. Both Cu(1)-S(3) bond lengths are 2.46 Å. Both Cu(1)-S(4) bond lengths are 2.51 Å. In the second Cu site, Cu(2) is bonded to two equivalent S(5) and four equivalent S(1) atoms to form CuS6 octahedra that share corners with four equivalent Ti(3)S6 octahedra, corners with eight equivalent Ti(2)S6 octahedra, and faces with two equivalent Ti(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. Both Cu(2)-S(5) bond lengths are 2.46 Å. All Cu(2)-S(1) bond lengths are 2.46 Å. There are five inequivalent S sites. In the first S site, S(5) is bonded in a rectangular see-saw-like geometry to one Ti(1), two equivalent Ti(2), and one Cu(2) atom. In the second S site, S(1) is bonded in a rectangular see-saw-like geometry to one Ti(1), one Ti(2), one Ti(3), and one Cu(2) atom. In the third S site, S(2) is bonded in a rectangular see-saw-like geometry to one Ti(3), two equivalent Ti(2), and one Cu(1) atom. In the fourth S site, S(3) is bonded in a rectangular see-saw-like geometry to one Ti(1), one Ti(2), one Ti(3), and one Cu(1) atom. In the fifth S site, S(4) is bonded to one Ti(1), two equivalent Ti(2), and two equivalent Cu(1) atoms to form distorted edge-sharing STi3Cu2 square pyramids.