MgV2CdO6 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one V(2)O5 trigonal bipyramid, corners with two equivalent Mg(1)O5 trigonal bipyramids, corners with two equivalent V(1)O5 trigonal bipyramids, and edges with two equivalent V(2)O5 trigonal bipyramids. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(3), one O(5), and two equivalent O(6) atoms to form distorted VO5 trigonal bipyramids that share corners with two equivalent Mg(1)O5 trigonal bipyramids, corners with two equivalent V(1)O5 trigonal bipyramids, and edges with two equivalent V(2)O5 trigonal bipyramids. In the second V site, V(2) is bonded to one O(2), one O(4), one O(6), and two equivalent O(5) atoms to form distorted VO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with two equivalent V(2)O5 trigonal bipyramids, edges with two equivalent Mg(1)O5 trigonal bipyramids, and edges with two equivalent V(1)O5 trigonal bipyramids. Cd(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and two equivalent O(3) atoms. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one V(1) and one Cd(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one V(2), and one Cd(1) atom. In the third O site, O(3) is bonded to one Mg(1), one V(1), and two equivalent Cd(1) atoms to form distorted corner-sharing OMgVCd2 tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Mg(1), one V(2), and one Cd(1) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to one Mg(1), one V(1), and two equivalent V(2) atoms. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one V(2), two equivalent V(1), and one Cd(1) atom.
MgV2CdO6 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one V(2)O5 trigonal bipyramid, corners with two equivalent Mg(1)O5 trigonal bipyramids, corners with two equivalent V(1)O5 trigonal bipyramids, and edges with two equivalent V(2)O5 trigonal bipyramids. The Mg(1)-O(2) bond length is 1.98 Å. The Mg(1)-O(3) bond length is 2.07 Å. The Mg(1)-O(5) bond length is 2.18 Å. Both Mg(1)-O(4) bond lengths are 2.02 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(5), and two equivalent O(6) atoms to form distorted VO5 trigonal bipyramids that share corners with two equivalent Mg(1)O5 trigonal bipyramids, corners with two equivalent V(1)O5 trigonal bipyramids, and edges with two equivalent V(2)O5 trigonal bipyramids. The V(1)-O(1) bond length is 1.68 Å. The V(1)-O(3) bond length is 1.91 Å. The V(1)-O(5) bond length is 1.96 Å. Both V(1)-O(6) bond lengths are 2.05 Å. In the second V site, V(2) is bonded to one O(2), one O(4), one O(6), and two equivalent O(5) atoms to form distorted VO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 trigonal bipyramid, corners with two equivalent V(2)O5 trigonal bipyramids, edges with two equivalent Mg(1)O5 trigonal bipyramids, and edges with two equivalent V(1)O5 trigonal bipyramids. The V(2)-O(2) bond length is 1.76 Å. The V(2)-O(4) bond length is 1.83 Å. The V(2)-O(6) bond length is 1.95 Å. Both V(2)-O(5) bond lengths are 2.02 Å. Cd(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and two equivalent O(3) atoms. The Cd(1)-O(1) bond length is 2.22 Å. The Cd(1)-O(2) bond length is 2.34 Å. The Cd(1)-O(4) bond length is 2.63 Å. The Cd(1)-O(6) bond length is 2.45 Å. Both Cd(1)-O(3) bond lengths are 2.25 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one V(1) and one Cd(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one V(2), and one Cd(1) atom. In the third O site, O(3) is bonded to one Mg(1), one V(1), and two equivalent Cd(1) atoms to form distorted corner-sharing OMgVCd2 tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Mg(1), one V(2), and one Cd(1) atom. In the fifth O site, O(5) is bonded in a distorted see-saw-like geometry to one Mg(1), one V(1), and two equivalent V(2) atoms. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one V(2), two equivalent V(1), and one Cd(1) atom.