Cu4SnS4 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted trigonal planar geometry to one S(1) and two equivalent S(2) atoms. In the second Cu site, Cu(2) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form CuS4 tetrahedra that share corners with four equivalent Cu(2)S4 tetrahedra and corners with four equivalent Sn(1)S4 tetrahedra. In the third Cu site, Cu(3) is bonded in a 4-coordinate geometry to one S(1), one S(3), and two equivalent S(2) atoms. Sn(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form SnS4 tetrahedra that share corners with eight equivalent Cu(2)S4 tetrahedra. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Cu(1), one Cu(3), two equivalent Cu(2), and one Sn(1) atom to form corner-sharing SCu4Sn trigonal bipyramids. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Cu(1), one Cu(3), two equivalent Cu(2), and one Sn(1) atom. In the third S site, S(3) is bonded to one Cu(3), two equivalent Cu(2), and one Sn(1) atom to form corner-sharing SCu3Sn tetrahedra.
Cu4SnS4 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted trigonal planar geometry to one S(1) and two equivalent S(2) atoms. The Cu(1)-S(1) bond length is 2.25 Å. Both Cu(1)-S(2) bond lengths are 2.29 Å. In the second Cu site, Cu(2) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form CuS4 tetrahedra that share corners with four equivalent Cu(2)S4 tetrahedra and corners with four equivalent Sn(1)S4 tetrahedra. The Cu(2)-S(1) bond length is 2.39 Å. The Cu(2)-S(3) bond length is 2.26 Å. There is one shorter (2.33 Å) and one longer (2.34 Å) Cu(2)-S(2) bond length. In the third Cu site, Cu(3) is bonded in a 4-coordinate geometry to one S(1), one S(3), and two equivalent S(2) atoms. The Cu(3)-S(1) bond length is 2.29 Å. The Cu(3)-S(3) bond length is 2.23 Å. Both Cu(3)-S(2) bond lengths are 2.52 Å. Sn(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form SnS4 tetrahedra that share corners with eight equivalent Cu(2)S4 tetrahedra. The Sn(1)-S(1) bond length is 2.50 Å. The Sn(1)-S(3) bond length is 2.49 Å. Both Sn(1)-S(2) bond lengths are 2.49 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Cu(1), one Cu(3), two equivalent Cu(2), and one Sn(1) atom to form corner-sharing SCu4Sn trigonal bipyramids. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Cu(1), one Cu(3), two equivalent Cu(2), and one Sn(1) atom. In the third S site, S(3) is bonded to one Cu(3), two equivalent Cu(2), and one Sn(1) atom to form corner-sharing SCu3Sn tetrahedra.