MgCu4(O3Cl)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), four equivalent O(1), and two equivalent Cl(1) atoms. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted edge-sharing CuO6 octahedra. In the second Cu site, Cu(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent Cl(1) atoms to form distorted CuCl2O4 octahedra that share edges with two equivalent Cu(2)Cl2O4 octahedra and edges with two equivalent Cu(1)O6 octahedra. In the third Cu site, Cu(3) is bonded in a distorted square co-planar geometry to four equivalent O(1) and two equivalent Cl(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Mg(1), one Cu(1), one Cu(2), and one Cu(3) atom. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to one Mg(1), one Cu(1), and two equivalent Cu(2) atoms. Cl(1) is bonded in a 4-coordinate geometry to one Mg(1), one Cu(3), and two equivalent Cu(2) atoms.
MgCu4(O3Cl)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(2), four equivalent O(1), and two equivalent Cl(1) atoms. Both Mg(1)-O(2) bond lengths are 2.23 Å. All Mg(1)-O(1) bond lengths are 2.24 Å. Both Mg(1)-Cl(1) bond lengths are 2.82 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form distorted edge-sharing CuO6 octahedra. Both Cu(1)-O(2) bond lengths are 2.17 Å. All Cu(1)-O(1) bond lengths are 2.15 Å. In the second Cu site, Cu(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent Cl(1) atoms to form distorted CuCl2O4 octahedra that share edges with two equivalent Cu(2)Cl2O4 octahedra and edges with two equivalent Cu(1)O6 octahedra. Both Cu(2)-O(1) bond lengths are 1.88 Å. Both Cu(2)-O(2) bond lengths are 1.88 Å. Both Cu(2)-Cl(1) bond lengths are 2.63 Å. In the third Cu site, Cu(3) is bonded in a distorted square co-planar geometry to four equivalent O(1) and two equivalent Cl(1) atoms. All Cu(3)-O(1) bond lengths are 1.88 Å. Both Cu(3)-Cl(1) bond lengths are 2.64 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Mg(1), one Cu(1), one Cu(2), and one Cu(3) atom. In the second O site, O(2) is bonded in a distorted see-saw-like geometry to one Mg(1), one Cu(1), and two equivalent Cu(2) atoms. Cl(1) is bonded in a 4-coordinate geometry to one Mg(1), one Cu(3), and two equivalent Cu(2) atoms.