MgCu4As2(O4Cl)2 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent Cl(1) atoms to form distorted MgCl2O4 octahedra that share corners with four equivalent As(1)O4 tetrahedra. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), and two equivalent Cl(1) atoms. In the second Cu site, Cu(2) is bonded in a distorted square co-planar geometry to two equivalent O(2), two equivalent O(3), and two equivalent Cl(1) atoms. In the third Cu site, Cu(3) is bonded in a distorted linear geometry to two equivalent O(1) and two equivalent Cl(1) atoms. As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share corners with two equivalent Mg(1)Cl2O4 octahedra. The corner-sharing octahedral tilt angles are 53°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(3), and one As(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cu(2), and one As(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one As(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cu(1), and one As(1) atom. Cl(1) is bonded in a 5-coordinate geometry to one Mg(1), one Cu(2), one Cu(3), and two equivalent Cu(1) atoms.
MgCu4As2(O4Cl)2 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent Cl(1) atoms to form distorted MgCl2O4 octahedra that share corners with four equivalent As(1)O4 tetrahedra. Both Mg(1)-O(2) bond lengths are 2.09 Å. Both Mg(1)-O(4) bond lengths are 2.08 Å. Both Mg(1)-Cl(1) bond lengths are 2.60 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), and two equivalent Cl(1) atoms. The Cu(1)-O(1) bond length is 2.13 Å. The Cu(1)-O(3) bond length is 2.11 Å. The Cu(1)-O(4) bond length is 2.02 Å. There is one shorter (2.32 Å) and one longer (2.53 Å) Cu(1)-Cl(1) bond length. In the second Cu site, Cu(2) is bonded in a distorted square co-planar geometry to two equivalent O(2), two equivalent O(3), and two equivalent Cl(1) atoms. Both Cu(2)-O(2) bond lengths are 2.01 Å. Both Cu(2)-O(3) bond lengths are 2.03 Å. Both Cu(2)-Cl(1) bond lengths are 2.78 Å. In the third Cu site, Cu(3) is bonded in a distorted linear geometry to two equivalent O(1) and two equivalent Cl(1) atoms. Both Cu(3)-O(1) bond lengths are 1.93 Å. Both Cu(3)-Cl(1) bond lengths are 2.75 Å. As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share corners with two equivalent Mg(1)Cl2O4 octahedra. The corner-sharing octahedral tilt angles are 53°. The As(1)-O(1) bond length is 1.73 Å. The As(1)-O(2) bond length is 1.75 Å. The As(1)-O(3) bond length is 1.74 Å. The As(1)-O(4) bond length is 1.72 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(3), and one As(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cu(2), and one As(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one As(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Cu(1), and one As(1) atom. Cl(1) is bonded in a 5-coordinate geometry to one Mg(1), one Cu(2), one Cu(3), and two equivalent Cu(1) atoms.