MgCr(WO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form MgO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra and  an edgeedge with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 22-62°. There are two inequivalent W sites. In the first W site, W(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. In the second W site, W(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted WO6 octahedra that share  a cornercorner with one Cr(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 25°. Cr(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 CrO6 octahedra that share  a cornercorner with one W(2)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, and edges with two equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles are 25°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Mg(1) and one W(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one W(1), and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped 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 non-coplanar geometry to one W(1), one W(2), and one Cr(1) atom. In the fifth O site, O(5) is bonded in a T-shaped geometry to one Mg(1), one W(2), and one Cr(1) atom. In the sixth O site, O(6) is bonded in a water-like geometry to one Mg(1) and one W(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one W(1), one W(2), and one Cr(1) atom. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one W(1), one W(2), and one Cr(1) atom.
MgCr(WO4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form MgO4 tetrahedra that share corners with two equivalent Cr(1)O6 octahedra and  an edgeedge with one W(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 22-62°. The Mg(1)-O(1) bond length is 1.97 Å. The Mg(1)-O(2) bond length is 1.97 Å. The Mg(1)-O(5) bond length is 2.04 Å. The Mg(1)-O(6) bond length is 2.06 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. The W(1)-O(1) bond length is 1.81 Å. The W(1)-O(2) bond length is 2.01 Å. The W(1)-O(3) bond length is 2.13 Å. The W(1)-O(4) bond length is 2.25 Å. The W(1)-O(7) bond length is 2.02 Å. The W(1)-O(8) bond length is 2.02 Å. In the second W site, W(2) is bonded to one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted WO6 octahedra that share  a cornercorner with one Cr(1)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 25°. The W(2)-O(3) bond length is 1.97 Å. The W(2)-O(4) bond length is 1.94 Å. The W(2)-O(5) bond length is 1.93 Å. The W(2)-O(6) bond length is 1.80 Å. The W(2)-O(7) bond length is 2.05 Å. The W(2)-O(8) bond length is 2.16 Å. Cr(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 CrO6 octahedra that share  a cornercorner with one W(2)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, and edges with two equivalent W(2)O6 octahedra. The corner-sharing octahedral tilt angles are 25°. The Cr(1)-O(2) bond length is 2.00 Å. The Cr(1)-O(3) bond length is 2.05 Å. The Cr(1)-O(4) bond length is 2.04 Å. The Cr(1)-O(5) bond length is 2.03 Å. The Cr(1)-O(7) bond length is 2.00 Å. The Cr(1)-O(8) bond length is 2.02 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Mg(1) and one W(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one W(1), and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped 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 non-coplanar geometry to one W(1), one W(2), and one Cr(1) atom. In the fifth O site, O(5) is bonded in a T-shaped geometry to one Mg(1), one W(2), and one Cr(1) atom. In the sixth O site, O(6) is bonded in a water-like geometry to one Mg(1) and one W(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one W(1), one W(2), and one Cr(1) atom. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one W(1), one W(2), and one Cr(1) atom.