MgV4(CoO6)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted MgO4 trigonal pyramids that share corners with two equivalent V(1)O4 tetrahedra, corners with two equivalent V(2)O4 tetrahedra, and  an edgeedge with one Co(1)O6 octahedra. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form VO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent V(2)O4 tetrahedra, and  a cornercorner with one Mg(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 49°. In the second V site, V(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form VO4 tetrahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent V(1)O4 tetrahedra, and  a cornercorner with one Mg(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 45-46°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 trigonal pyramid. In the second Co site, Co(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(6) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one V(1), one Co(1), and one Co(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Mg(1) and one V(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one V(2), and one Co(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one V(1) and one V(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one V(1) and one V(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one V(2), one Co(1), and one Co(2) atom.
MgV4(CoO6)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted MgO4 trigonal pyramids that share corners with two equivalent V(1)O4 tetrahedra, corners with two equivalent V(2)O4 tetrahedra, and  an edgeedge with one Co(1)O6 octahedra. Both Mg(1)-O(2) bond lengths are 1.95 Å. Both Mg(1)-O(3) bond lengths are 1.97 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form VO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent V(2)O4 tetrahedra, and  a cornercorner with one Mg(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles are 49°. The V(1)-O(1) bond length is 1.77 Å. The V(1)-O(2) bond length is 1.69 Å. The V(1)-O(4) bond length is 1.75 Å. The V(1)-O(5) bond length is 1.77 Å. In the second V site, V(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form VO4 tetrahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent V(1)O4 tetrahedra, and  a cornercorner with one Mg(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 45-46°. The V(2)-O(3) bond length is 1.76 Å. The V(2)-O(4) bond length is 1.88 Å. The V(2)-O(5) bond length is 1.89 Å. The V(2)-O(6) bond length is 1.79 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent V(1)O4 tetrahedra, corners with four equivalent V(2)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 trigonal pyramid. Both Co(1)-O(1) bond lengths are 2.02 Å. Both Co(1)-O(3) bond lengths are 2.21 Å. Both Co(1)-O(6) bond lengths are 2.25 Å. In the second Co site, Co(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(6) atoms. Both Co(2)-O(1) bond lengths are 1.97 Å. Both Co(2)-O(6) bond lengths are 1.97 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one V(1), one Co(1), and one Co(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Mg(1) and one V(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one V(2), and one Co(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one V(1) and one V(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one V(1) and one V(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one V(2), one Co(1), and one Co(2) atom.