MgV2Cu3O8 is Chalcostibite-derived structured and crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(6), one O(7), and one O(8) atom to form distorted MgO4 tetrahedra that share  a cornercorner with one V(2)O4 tetrahedra, corners with three equivalent V(1)O4 tetrahedra, corners with three equivalent Cu(2)O5 trigonal bipyramids, and  an edgeedge with one Cu(1)O5 trigonal bipyramid. 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)O4 tetrahedra, corners with two equivalent Cu(1)O5 trigonal bipyramids, and corners with three equivalent Cu(2)O5 trigonal bipyramids. In the second V site, V(2) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form VO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with two equivalent Cu(2)O5 trigonal bipyramids, and corners with three equivalent Cu(1)O5 trigonal bipyramids. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(2), one O(3), one O(5), and one O(8) atom to form distorted CuO5 trigonal bipyramids that share corners with two equivalent V(1)O4 tetrahedra, corners with three equivalent V(2)O4 tetrahedra,  an edgeedge with one Mg(1)O4 tetrahedra, and  an edgeedge with one Cu(2)O5 trigonal bipyramid. In the second Cu site, Cu(2) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(7) atom to form distorted CuO5 trigonal bipyramids that share corners with two equivalent V(2)O4 tetrahedra, corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent V(1)O4 tetrahedra, and  an edgeedge with one Cu(1)O5 trigonal bipyramid. In the third Cu site, Cu(3) is bonded in a rectangular see-saw-like geometry to one O(3), one O(4), one O(5), and one O(7) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one V(1), one Cu(1), and one Cu(2) atom to form distorted corner-sharing OMgVCu2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one V(2), one Cu(1), and one Cu(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one V(1), one Cu(1), and one Cu(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one V(2), one Cu(2), and one Cu(3) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one V(2), one Cu(1), and one Cu(3) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Mg(1), one V(1), and one Cu(2) atom. In the seventh O site, O(7) is bonded to one Mg(1), one V(1), one Cu(2), and one Cu(3) atom to form corner-sharing OMgVCu2 tetrahedra. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Mg(1), one V(2), and one Cu(1) atom.
MgV2Cu3O8 is Chalcostibite-derived structured and crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(6), one O(7), and one O(8) atom to form distorted MgO4 tetrahedra that share  a cornercorner with one V(2)O4 tetrahedra, corners with three equivalent V(1)O4 tetrahedra, corners with three equivalent Cu(2)O5 trigonal bipyramids, and  an edgeedge with one Cu(1)O5 trigonal bipyramid. The Mg(1)-O(1) bond length is 2.01 Å. The Mg(1)-O(6) bond length is 1.96 Å. The Mg(1)-O(7) bond length is 2.08 Å. The Mg(1)-O(8) bond length is 1.93 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)O4 tetrahedra, corners with two equivalent Cu(1)O5 trigonal bipyramids, and corners with three equivalent Cu(2)O5 trigonal bipyramids. The V(1)-O(1) bond length is 1.77 Å. The V(1)-O(3) bond length is 1.75 Å. The V(1)-O(6) bond length is 1.75 Å. The V(1)-O(7) bond length is 1.84 Å. In the second V site, V(2) is bonded to one O(2), one O(4), one O(5), and one O(8) atom to form VO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with two equivalent Cu(2)O5 trigonal bipyramids, and corners with three equivalent Cu(1)O5 trigonal bipyramids. The V(2)-O(2) bond length is 1.76 Å. The V(2)-O(4) bond length is 1.77 Å. The V(2)-O(5) bond length is 1.78 Å. The V(2)-O(8) bond length is 1.75 Å. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(2), one O(3), one O(5), and one O(8) atom to form distorted CuO5 trigonal bipyramids that share corners with two equivalent V(1)O4 tetrahedra, corners with three equivalent V(2)O4 tetrahedra,  an edgeedge with one Mg(1)O4 tetrahedra, and  an edgeedge with one Cu(2)O5 trigonal bipyramid. The Cu(1)-O(1) bond length is 2.20 Å. The Cu(1)-O(2) bond length is 2.03 Å. The Cu(1)-O(3) bond length is 2.03 Å. The Cu(1)-O(5) bond length is 2.01 Å. The Cu(1)-O(8) bond length is 2.25 Å. In the second Cu site, Cu(2) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(7) atom to form distorted CuO5 trigonal bipyramids that share corners with two equivalent V(2)O4 tetrahedra, corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent V(1)O4 tetrahedra, and  an edgeedge with one Cu(1)O5 trigonal bipyramid. The Cu(2)-O(1) bond length is 2.22 Å. The Cu(2)-O(2) bond length is 2.07 Å. The Cu(2)-O(4) bond length is 2.09 Å. The Cu(2)-O(6) bond length is 2.14 Å. The Cu(2)-O(7) bond length is 2.12 Å. In the third Cu site, Cu(3) is bonded in a rectangular see-saw-like geometry to one O(3), one O(4), one O(5), and one O(7) atom. The Cu(3)-O(3) bond length is 2.09 Å. The Cu(3)-O(4) bond length is 2.07 Å. The Cu(3)-O(5) bond length is 1.96 Å. The Cu(3)-O(7) bond length is 2.06 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one V(1), one Cu(1), and one Cu(2) atom to form distorted corner-sharing OMgVCu2 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one V(2), one Cu(1), and one Cu(2) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one V(1), one Cu(1), and one Cu(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one V(2), one Cu(2), and one Cu(3) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one V(2), one Cu(1), and one Cu(3) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Mg(1), one V(1), and one Cu(2) atom. In the seventh O site, O(7) is bonded to one Mg(1), one V(1), one Cu(2), and one Cu(3) atom to form corner-sharing OMgVCu2 tetrahedra. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Mg(1), one V(2), and one Cu(1) atom.