Mg3V2O7 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to one O(4), two equivalent O(3), and three equivalent O(2) atoms. V(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form corner-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 38-42°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1) and two equivalent V(1) atoms to form distorted OMg2V2 tetrahedra that share corners with two equivalent O(1)Mg2V2 tetrahedra and corners with two equivalent O(2)Mg3V tetrahedra. In the second O site, O(2) is bonded to three equivalent Mg(2) and one V(1) atom to form distorted OMg3V tetrahedra that share  a cornercorner with one O(1)Mg2V2 tetrahedra and corners with six equivalent O(2)Mg3V tetrahedra. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Mg(2), and two equivalent V(1) atoms. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent V(1) atoms.
Mg3V2O7 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(4) atoms. There is one shorter (2.08 Å) and one longer (2.18 Å) Mg(1)-O(1) bond length. Both Mg(1)-O(3) bond lengths are 2.62 Å. There are two shorter (2.07 Å) and two longer (2.59 Å) Mg(1)-O(4) bond lengths. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to one O(4), two equivalent O(3), and three equivalent O(2) atoms. The Mg(2)-O(4) bond length is 2.27 Å. There is one shorter (2.04 Å) and one longer (2.40 Å) Mg(2)-O(3) bond length. There are a spread of Mg(2)-O(2) bond distances ranging from 2.03-2.11 Å. V(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form corner-sharing VO6 octahedra. The corner-sharing octahedral tilt angles range from 38-42°. The V(1)-O(1) bond length is 1.97 Å. The V(1)-O(2) bond length is 1.90 Å. There is one shorter (1.95 Å) and one longer (2.00 Å) V(1)-O(3) bond length. There is one shorter (1.98 Å) and one longer (2.01 Å) V(1)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1) and two equivalent V(1) atoms to form distorted OMg2V2 tetrahedra that share corners with two equivalent O(1)Mg2V2 tetrahedra and corners with two equivalent O(2)Mg3V tetrahedra. In the second O site, O(2) is bonded to three equivalent Mg(2) and one V(1) atom to form distorted OMg3V tetrahedra that share  a cornercorner with one O(1)Mg2V2 tetrahedra and corners with six equivalent O(2)Mg3V tetrahedra. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Mg(2), and two equivalent V(1) atoms. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent V(1) atoms.