MgCu2(WO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(5), one O(6), and one O(7) atom to form distorted MgO4 trigonal pyramids that share  a cornercorner with one W(2)O6 octahedra, corners with two equivalent W(1)O6 octahedra, corners with two equivalent Cu(1)O4 tetrahedra, and  an edgeedge with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 20-50°. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(2), 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 Cu(1)O4 tetrahedra, corners with two equivalent Mg(1)O4 trigonal pyramids, and edges with two equivalent W(2)O6 octahedra. In the second W site, W(2) is bonded to one O(1), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form WO6 octahedra that share corners with three equivalent Cu(1)O4 tetrahedra,  a cornercorner with one Mg(1)O4 trigonal pyramid, edges with two equivalent W(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 trigonal pyramid. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form distorted CuO4 tetrahedra that share corners with two equivalent W(1)O6 octahedra, corners with three equivalent W(2)O6 octahedra, and corners with two equivalent Mg(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 37-67°. In the second Cu site, Cu(2) is bonded in a distorted trigonal planar geometry to one O(1), one O(3), one O(4), and one O(5) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one W(1), one W(2), and one Cu(2) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one W(1), one W(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one W(2), one Cu(1), and one Cu(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one W(1), one Cu(1), and one Cu(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one W(1), and one Cu(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mg(1), one W(2), and one Cu(1) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Mg(1), one W(1), and one W(2) atom. In the eighth O site, O(8) is bonded in a water-like geometry to one W(1) and one W(2) atom.
MgCu2(WO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(5), one O(6), and one O(7) atom to form distorted MgO4 trigonal pyramids that share  a cornercorner with one W(2)O6 octahedra, corners with two equivalent W(1)O6 octahedra, corners with two equivalent Cu(1)O4 tetrahedra, and  an edgeedge with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 20-50°. The Mg(1)-O(3) bond length is 2.09 Å. The Mg(1)-O(5) bond length is 1.99 Å. The Mg(1)-O(6) bond length is 1.95 Å. The Mg(1)-O(7) bond length is 1.98 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(1), one O(2), 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 Cu(1)O4 tetrahedra, corners with two equivalent Mg(1)O4 trigonal pyramids, and edges with two equivalent W(2)O6 octahedra. The W(1)-O(1) bond length is 1.98 Å. The W(1)-O(2) bond length is 2.15 Å. The W(1)-O(4) bond length is 1.87 Å. The W(1)-O(5) bond length is 1.87 Å. The W(1)-O(7) bond length is 2.06 Å. The W(1)-O(8) bond length is 1.93 Å. In the second W site, W(2) is bonded to one O(1), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form WO6 octahedra that share corners with three equivalent Cu(1)O4 tetrahedra,  a cornercorner with one Mg(1)O4 trigonal pyramid, edges with two equivalent W(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 trigonal pyramid. The W(2)-O(1) bond length is 2.06 Å. The W(2)-O(2) bond length is 1.96 Å. The W(2)-O(3) bond length is 1.87 Å. The W(2)-O(6) bond length is 1.88 Å. The W(2)-O(7) bond length is 2.06 Å. The W(2)-O(8) bond length is 2.00 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form distorted CuO4 tetrahedra that share corners with two equivalent W(1)O6 octahedra, corners with three equivalent W(2)O6 octahedra, and corners with two equivalent Mg(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 37-67°. The Cu(1)-O(2) bond length is 1.93 Å. The Cu(1)-O(3) bond length is 2.44 Å. The Cu(1)-O(4) bond length is 1.92 Å. The Cu(1)-O(6) bond length is 2.10 Å. In the second Cu site, Cu(2) is bonded in a distorted trigonal planar geometry to one O(1), one O(3), one O(4), and one O(5) atom. The Cu(2)-O(1) bond length is 1.97 Å. The Cu(2)-O(3) bond length is 2.62 Å. The Cu(2)-O(4) bond length is 1.93 Å. The Cu(2)-O(5) bond length is 2.06 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one W(1), one W(2), and one Cu(2) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one W(1), one W(2), and one Cu(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one W(2), one Cu(1), and one Cu(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one W(1), one Cu(1), and one Cu(2) atom. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1), one W(1), and one Cu(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Mg(1), one W(2), and one Cu(1) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Mg(1), one W(1), and one W(2) atom. In the eighth O site, O(8) is bonded in a water-like geometry to one W(1) and one W(2) atom.