MgCr2Cu2(WO4)4 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(5), two equivalent O(7), and two equivalent O(8) atoms to form distorted MgO6 octahedra that share corners with four equivalent W(2)O6 octahedra,  an edgeedge with one Cr(1)O6 octahedra,  an edgeedge with one Cu(1)O6 octahedra, edges with two equivalent Cu(2)O6 octahedra, and faces with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-45°. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted WO6 octahedra that share corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Cu(1)O6 octahedra, corners with two equivalent Cu(2)O6 octahedra, edges with two equivalent W(2)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-59°. In the second W site, W(2) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form WO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Cu(1)O6 octahedra, corners with two equivalent Cu(2)O6 octahedra, and edges with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-57°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form CrO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Cu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-53°. In the second Cr site, Cr(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, and edges with two equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-59°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms to form distorted CuO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-56°. In the second Cu site, Cu(2) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(8) atoms to form CuO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-57°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one W(2), one Cr(1), and one Cu(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one W(1), one Cr(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one W(1), one W(2), and one Cr(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one W(1), one W(2), and one Cr(2) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(1), one W(1), one Cr(1), and one Cu(2) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one W(2), one Cr(2), and one Cu(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Mg(1), one W(1), one W(2), and one Cu(1) atom. In the eighth O site, O(8) is bonded to one Mg(1), one W(1), one W(2), and one Cu(2) atom to form distorted corner-sharing OMgCuW2 trigonal pyramids.
MgCr2Cu2(WO4)4 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(5), two equivalent O(7), and two equivalent O(8) atoms to form distorted MgO6 octahedra that share corners with four equivalent W(2)O6 octahedra,  an edgeedge with one Cr(1)O6 octahedra,  an edgeedge with one Cu(1)O6 octahedra, edges with two equivalent Cu(2)O6 octahedra, and faces with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-45°. Both Mg(1)-O(5) bond lengths are 2.07 Å. Both Mg(1)-O(7) bond lengths are 2.10 Å. Both Mg(1)-O(8) bond lengths are 2.04 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted WO6 octahedra that share corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Cu(1)O6 octahedra, corners with two equivalent Cu(2)O6 octahedra, edges with two equivalent W(2)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-59°. The W(1)-O(2) bond length is 1.84 Å. The W(1)-O(3) bond length is 2.09 Å. The W(1)-O(4) bond length is 2.04 Å. The W(1)-O(5) bond length is 2.04 Å. The W(1)-O(7) bond length is 2.17 Å. The W(1)-O(8) bond length is 2.02 Å. In the second W site, W(2) is bonded to one O(1), one O(3), one O(4), one O(6), one O(7), and one O(8) atom to form WO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Cr(1)O6 octahedra, corners with two equivalent Cr(2)O6 octahedra, corners with two equivalent Cu(1)O6 octahedra, corners with two equivalent Cu(2)O6 octahedra, and edges with two equivalent W(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-57°. The W(2)-O(1) bond length is 1.86 Å. The W(2)-O(3) bond length is 2.02 Å. The W(2)-O(4) bond length is 2.12 Å. The W(2)-O(6) bond length is 1.86 Å. The W(2)-O(7) bond length is 1.97 Å. The W(2)-O(8) bond length is 2.08 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form CrO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Cu(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-53°. Both Cr(1)-O(1) bond lengths are 2.03 Å. Both Cr(1)-O(3) bond lengths are 2.10 Å. Both Cr(1)-O(5) bond lengths are 2.05 Å. In the second Cr site, Cr(2) is bonded to two equivalent O(2), two equivalent O(4), and two equivalent O(6) atoms to form CrO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, and edges with two equivalent Cu(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-59°. Both Cr(2)-O(2) bond lengths are 1.98 Å. Both Cr(2)-O(4) bond lengths are 2.04 Å. Both Cr(2)-O(6) bond lengths are 2.05 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms to form distorted CuO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-56°. Both Cu(1)-O(2) bond lengths are 2.07 Å. Both Cu(1)-O(6) bond lengths are 2.22 Å. Both Cu(1)-O(7) bond lengths are 2.33 Å. In the second Cu site, Cu(2) is bonded to two equivalent O(1), two equivalent O(5), and two equivalent O(8) atoms to form CuO6 octahedra that share corners with four equivalent W(1)O6 octahedra, corners with four equivalent W(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-57°. Both Cu(2)-O(1) bond lengths are 2.17 Å. Both Cu(2)-O(5) bond lengths are 2.12 Å. Both Cu(2)-O(8) bond lengths are 2.38 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one W(2), one Cr(1), and one Cu(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one W(1), one Cr(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one W(1), one W(2), and one Cr(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one W(1), one W(2), and one Cr(2) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(1), one W(1), one Cr(1), and one Cu(2) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one W(2), one Cr(2), and one Cu(1) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Mg(1), one W(1), one W(2), and one Cu(1) atom. In the eighth O site, O(8) is bonded to one Mg(1), one W(1), one W(2), and one Cu(2) atom to form distorted corner-sharing OMgCuW2 trigonal pyramids.