Mg2V2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form MgO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra, and edges with two equivalent Mg(2)O6 octahedra. In the second Mg site, Mg(2) is bonded to one O(2), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form MgO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra, corners with three equivalent V(2)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form VO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and  a cornercorner with one V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-61°. In the second V site, V(2) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form VO4 tetrahedra that share corners with three equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, and  a cornercorner with one V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 43-60°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Mg(2) and one V(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one V(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one V(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one V(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one V(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one V(1) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Mg(1), one V(1), and one V(2) atom.
Mg2V2O7 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form MgO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra, and edges with two equivalent Mg(2)O6 octahedra. The Mg(1)-O(2) bond length is 2.15 Å. The Mg(1)-O(3) bond length is 2.04 Å. The Mg(1)-O(4) bond length is 2.10 Å. The Mg(1)-O(5) bond length is 2.15 Å. The Mg(1)-O(6) bond length is 2.10 Å. The Mg(1)-O(7) bond length is 2.21 Å. In the second Mg site, Mg(2) is bonded to one O(2), one O(4), one O(5), one O(6), and two equivalent O(1) atoms to form MgO6 octahedra that share corners with three equivalent V(1)O4 tetrahedra, corners with three equivalent V(2)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The Mg(2)-O(2) bond length is 2.11 Å. The Mg(2)-O(4) bond length is 2.11 Å. The Mg(2)-O(5) bond length is 2.11 Å. The Mg(2)-O(6) bond length is 2.10 Å. Both Mg(2)-O(1) bond lengths are 2.09 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form VO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and  a cornercorner with one V(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-61°. The V(1)-O(1) bond length is 1.73 Å. The V(1)-O(3) bond length is 1.67 Å. The V(1)-O(6) bond length is 1.74 Å. The V(1)-O(7) bond length is 1.89 Å. In the second V site, V(2) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form VO4 tetrahedra that share corners with three equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, and  a cornercorner with one V(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 43-60°. The V(2)-O(2) bond length is 1.73 Å. The V(2)-O(4) bond length is 1.72 Å. The V(2)-O(5) bond length is 1.72 Å. The V(2)-O(7) bond length is 1.87 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Mg(2) and one V(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one V(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one V(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one V(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one V(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(2), and one V(1) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Mg(1), one V(1), and one V(2) atom.