Cu5Se4(O6Cl)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted CuO5 square pyramids that share  a cornercorner with one Cu(2)O6 octahedra,  an edgeedge with one Cu(2)O6 octahedra, and  an edgeedge with one Cu(3)Cl2O3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 53°. In the second Cu site, Cu(2) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing CuO6 octahedra. In the third Cu site, Cu(3) is bonded to one O(1), one O(2), one O(6), and two equivalent Cl(1) atoms to form CuCl2O3 trigonal bipyramids that share  an edgeedge with one Cu(1)O5 square pyramid and  an edgeedge with one Cu(3)Cl2O3 trigonal bipyramid. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. In the second Se site, Se(2) is bonded in a 3-coordinate geometry to one O(4), one O(5), and one O(6) atom. There are six inequivalent O sites. In the first O site, O(4) is bonded in a trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the second O site, O(5) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the third O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one Cu(3), and one Se(2) atom. In the fourth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cu(3) and one Se(1) atom. In the fifth O site, O(2) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(3), and one Se(1) atom. In the sixth O site, O(3) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one Se(1) atom. Cl(1) is bonded in an L-shaped geometry to two equivalent Cu(3) atoms.
Cu5Se4(O6Cl)2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted CuO5 square pyramids that share  a cornercorner with one Cu(2)O6 octahedra,  an edgeedge with one Cu(2)O6 octahedra, and  an edgeedge with one Cu(3)Cl2O3 trigonal bipyramid. The corner-sharing octahedral tilt angles are 53°. The Cu(1)-O(2) bond length is 1.91 Å. The Cu(1)-O(3) bond length is 1.97 Å. The Cu(1)-O(4) bond length is 1.96 Å. The Cu(1)-O(5) bond length is 2.04 Å. The Cu(1)-O(6) bond length is 2.36 Å. In the second Cu site, Cu(2) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form a mixture of corner and edge-sharing CuO6 octahedra. Both Cu(2)-O(3) bond lengths are 2.37 Å. Both Cu(2)-O(4) bond lengths are 1.99 Å. Both Cu(2)-O(5) bond lengths are 1.96 Å. In the third Cu site, Cu(3) is bonded to one O(1), one O(2), one O(6), and two equivalent Cl(1) atoms to form CuCl2O3 trigonal bipyramids that share  an edgeedge with one Cu(1)O5 square pyramid and  an edgeedge with one Cu(3)Cl2O3 trigonal bipyramid. The Cu(3)-O(1) bond length is 1.94 Å. The Cu(3)-O(2) bond length is 2.26 Å. The Cu(3)-O(6) bond length is 1.97 Å. There is one shorter (2.28 Å) and one longer (2.30 Å) Cu(3)-Cl(1) bond length. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. The Se(1)-O(1) bond length is 1.71 Å. The Se(1)-O(2) bond length is 1.72 Å. The Se(1)-O(3) bond length is 1.71 Å. In the second Se site, Se(2) is bonded in a 3-coordinate geometry to one O(4), one O(5), and one O(6) atom. The Se(2)-O(4) bond length is 1.76 Å. The Se(2)-O(5) bond length is 1.76 Å. The Se(2)-O(6) bond length is 1.70 Å. There are six inequivalent O sites. In the first O site, O(4) is bonded in a trigonal non-coplanar geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the second O site, O(5) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one Se(2) atom. In the third O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Cu(1), one Cu(3), and one Se(2) atom. In the fourth O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cu(3) and one Se(1) atom. In the fifth O site, O(2) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(3), and one Se(1) atom. In the sixth O site, O(3) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one Se(1) atom. Cl(1) is bonded in an L-shaped geometry to two equivalent Cu(3) atoms.