MgV2Cd2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(7) atom to form distorted MgO5 square pyramids that share  a cornercorner with one V(1)O5 trigonal bipyramid, corners with two equivalent V(2)O5 trigonal bipyramids,  an edgeedge with one V(1)O5 trigonal bipyramid, and  an edgeedge with one V(2)O5 trigonal bipyramid. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form distorted VO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 square pyramid,  a cornercorner with one V(2)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O5 square pyramid, and  an edgeedge with one V(2)O5 trigonal bipyramid. In the second V site, V(2) is bonded to one O(1), one O(4), one O(5), one O(6), and one O(7) atom to form VO5 trigonal bipyramids that share corners with two equivalent Mg(1)O5 square pyramids,  a cornercorner with one V(1)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O5 square pyramid, and  an edgeedge with one V(1)O5 trigonal bipyramid. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. In the second Cd site, Cd(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(6), and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one V(2), one Cd(1), and one Cd(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one V(1), one Cd(1), and one Cd(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one V(1), one Cd(1), and one Cd(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one V(2), and one Cd(1) atom. In the fifth O site, O(5) is bonded in a T-shaped geometry to one Mg(1), one V(1), and one V(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal pyramidal geometry to one V(1), one V(2), one Cd(1), and one Cd(2) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Mg(1), one V(1), one V(2), one Cd(1), and one Cd(2) atom.
MgV2Cd2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(7) atom to form distorted MgO5 square pyramids that share  a cornercorner with one V(1)O5 trigonal bipyramid, corners with two equivalent V(2)O5 trigonal bipyramids,  an edgeedge with one V(1)O5 trigonal bipyramid, and  an edgeedge with one V(2)O5 trigonal bipyramid. The Mg(1)-O(1) bond length is 2.09 Å. The Mg(1)-O(3) bond length is 2.05 Å. The Mg(1)-O(4) bond length is 2.06 Å. The Mg(1)-O(5) bond length is 2.03 Å. The Mg(1)-O(7) bond length is 2.15 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form distorted VO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5 square pyramid,  a cornercorner with one V(2)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O5 square pyramid, and  an edgeedge with one V(2)O5 trigonal bipyramid. The V(1)-O(2) bond length is 1.78 Å. The V(1)-O(3) bond length is 1.84 Å. The V(1)-O(5) bond length is 1.89 Å. The V(1)-O(6) bond length is 2.16 Å. The V(1)-O(7) bond length is 1.96 Å. In the second V site, V(2) is bonded to one O(1), one O(4), one O(5), one O(6), and one O(7) atom to form VO5 trigonal bipyramids that share corners with two equivalent Mg(1)O5 square pyramids,  a cornercorner with one V(1)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O5 square pyramid, and  an edgeedge with one V(1)O5 trigonal bipyramid. The V(2)-O(1) bond length is 1.89 Å. The V(2)-O(4) bond length is 1.85 Å. The V(2)-O(5) bond length is 1.91 Å. The V(2)-O(6) bond length is 1.82 Å. The V(2)-O(7) bond length is 2.19 Å. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. The Cd(1)-O(1) bond length is 2.35 Å. The Cd(1)-O(2) bond length is 2.23 Å. The Cd(1)-O(3) bond length is 2.41 Å. The Cd(1)-O(4) bond length is 2.24 Å. The Cd(1)-O(6) bond length is 2.38 Å. The Cd(1)-O(7) bond length is 2.62 Å. In the second Cd site, Cd(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(6), and one O(7) atom. The Cd(2)-O(1) bond length is 2.28 Å. The Cd(2)-O(2) bond length is 2.26 Å. The Cd(2)-O(3) bond length is 2.27 Å. The Cd(2)-O(6) bond length is 2.27 Å. The Cd(2)-O(7) bond length is 2.47 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one V(2), one Cd(1), and one Cd(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one V(1), one Cd(1), and one Cd(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one V(1), one Cd(1), and one Cd(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Mg(1), one V(2), and one Cd(1) atom. In the fifth O site, O(5) is bonded in a T-shaped geometry to one Mg(1), one V(1), and one V(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal pyramidal geometry to one V(1), one V(2), one Cd(1), and one Cd(2) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Mg(1), one V(1), one V(2), one Cd(1), and one Cd(2) atom.