MgW2O7 crystallizes in the monoclinic P2_1 space group. Mg(1) is bonded to one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent W(2)O4 tetrahedra, corners with three equivalent W(1)O4 tetrahedra, and corners with two equivalent Mg(1)O5 trigonal bipyramids. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(4), one O(6), and one O(7) atom to form WO4 tetrahedra that share  a cornercorner with one W(2)O4 tetrahedra and corners with three equivalent Mg(1)O5 trigonal bipyramids. In the second W site, W(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form WO4 tetrahedra that share  a cornercorner with one W(1)O4 tetrahedra and corners with two equivalent Mg(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one W(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one W(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Mg(1) and one W(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(1) and one W(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Mg(1) and one W(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one W(1) and one W(2) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one W(1) atom.
MgW2O7 crystallizes in the monoclinic P2_1 space group. Mg(1) is bonded to one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent W(2)O4 tetrahedra, corners with three equivalent W(1)O4 tetrahedra, and corners with two equivalent Mg(1)O5 trigonal bipyramids. The Mg(1)-O(3) bond length is 2.02 Å. The Mg(1)-O(4) bond length is 2.05 Å. The Mg(1)-O(5) bond length is 2.01 Å. There is one shorter (2.01 Å) and one longer (2.50 Å) Mg(1)-O(2) bond length. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(4), one O(6), and one O(7) atom to form WO4 tetrahedra that share  a cornercorner with one W(2)O4 tetrahedra and corners with three equivalent Mg(1)O5 trigonal bipyramids. The W(1)-O(2) bond length is 1.85 Å. The W(1)-O(4) bond length is 1.80 Å. The W(1)-O(6) bond length is 1.94 Å. The W(1)-O(7) bond length is 1.74 Å. In the second W site, W(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form WO4 tetrahedra that share  a cornercorner with one W(1)O4 tetrahedra and corners with two equivalent Mg(1)O5 trigonal bipyramids. The W(2)-O(1) bond length is 1.74 Å. The W(2)-O(3) bond length is 1.81 Å. The W(2)-O(5) bond length is 1.83 Å. The W(2)-O(6) bond length is 1.94 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one W(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one W(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Mg(1) and one W(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mg(1) and one W(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Mg(1) and one W(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one W(1) and one W(2) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one W(1) atom.