MgV4(CuS4)2 crystallizes in the orthorhombic Imm2 space group. Mg(1) is bonded to two equivalent S(3) and two equivalent S(4) atoms to form distorted MgS4 tetrahedra that share corners with six equivalent V(1)S6 octahedra, corners with two equivalent Cu(1)S4 tetrahedra, and  an edgeedge with one Cu(2)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 38-62°. There are two inequivalent V sites. In the first V site, V(1) is bonded to one S(2), one S(3), two equivalent S(1), and two equivalent S(4) atoms to form VS6 octahedra that share corners with three equivalent Mg(1)S4 tetrahedra, corners with three equivalent Cu(1)S4 tetrahedra, corners with three equivalent Cu(2)S4 tetrahedra, and edges with two equivalent V(1)S6 octahedra. In the second V site, V(2) is bonded in a 5-coordinate geometry to one S(1), two equivalent S(2), and two equivalent S(3) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent S(1) and two equivalent S(3) atoms to form CuS4 tetrahedra that share corners with six equivalent V(1)S6 octahedra and corners with two equivalent Mg(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-58°. In the second Cu site, Cu(2) is bonded to two equivalent S(2) and two equivalent S(4) atoms to form distorted CuS4 tetrahedra that share corners with six equivalent V(1)S6 octahedra and  an edgeedge with one Mg(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-64°. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one V(2), two equivalent V(1), and one Cu(1) atom. In the second S site, S(2) is bonded to one V(1), two equivalent V(2), and one Cu(2) atom to form SV3Cu tetrahedra that share  a cornercorner with one S(2)V3Cu tetrahedra, corners with four equivalent S(4)MgV2Cu tetrahedra, and  an edgeedge with one S(2)V3Cu tetrahedra. In the third S site, S(3) is bonded in a distorted pentagonal planar geometry to one Mg(1), one V(1), two equivalent V(2), and one Cu(1) atom. In the fourth S site, S(4) is bonded to one Mg(1), two equivalent V(1), and one Cu(2) atom to form distorted SMgV2Cu tetrahedra that share corners with four equivalent S(2)V3Cu tetrahedra and edges with two equivalent S(4)MgV2Cu tetrahedra.
MgV4(CuS4)2 crystallizes in the orthorhombic Imm2 space group. Mg(1) is bonded to two equivalent S(3) and two equivalent S(4) atoms to form distorted MgS4 tetrahedra that share corners with six equivalent V(1)S6 octahedra, corners with two equivalent Cu(1)S4 tetrahedra, and  an edgeedge with one Cu(2)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 38-62°. Both Mg(1)-S(3) bond lengths are 2.47 Å. Both Mg(1)-S(4) bond lengths are 2.34 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one S(2), one S(3), two equivalent S(1), and two equivalent S(4) atoms to form VS6 octahedra that share corners with three equivalent Mg(1)S4 tetrahedra, corners with three equivalent Cu(1)S4 tetrahedra, corners with three equivalent Cu(2)S4 tetrahedra, and edges with two equivalent V(1)S6 octahedra. The V(1)-S(2) bond length is 2.57 Å. The V(1)-S(3) bond length is 2.43 Å. Both V(1)-S(1) bond lengths are 2.40 Å. Both V(1)-S(4) bond lengths are 2.44 Å. In the second V site, V(2) is bonded in a 5-coordinate geometry to one S(1), two equivalent S(2), and two equivalent S(3) atoms. The V(2)-S(1) bond length is 2.30 Å. Both V(2)-S(2) bond lengths are 2.37 Å. Both V(2)-S(3) bond lengths are 2.49 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to two equivalent S(1) and two equivalent S(3) atoms to form CuS4 tetrahedra that share corners with six equivalent V(1)S6 octahedra and corners with two equivalent Mg(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 52-58°. Both Cu(1)-S(1) bond lengths are 2.31 Å. Both Cu(1)-S(3) bond lengths are 2.29 Å. In the second Cu site, Cu(2) is bonded to two equivalent S(2) and two equivalent S(4) atoms to form distorted CuS4 tetrahedra that share corners with six equivalent V(1)S6 octahedra and  an edgeedge with one Mg(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-64°. Both Cu(2)-S(2) bond lengths are 2.27 Å. Both Cu(2)-S(4) bond lengths are 2.41 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one V(2), two equivalent V(1), and one Cu(1) atom. In the second S site, S(2) is bonded to one V(1), two equivalent V(2), and one Cu(2) atom to form SV3Cu tetrahedra that share  a cornercorner with one S(2)V3Cu tetrahedra, corners with four equivalent S(4)MgV2Cu tetrahedra, and  an edgeedge with one S(2)V3Cu tetrahedra. In the third S site, S(3) is bonded in a distorted pentagonal planar geometry to one Mg(1), one V(1), two equivalent V(2), and one Cu(1) atom. In the fourth S site, S(4) is bonded to one Mg(1), two equivalent V(1), and one Cu(2) atom to form distorted SMgV2Cu tetrahedra that share corners with four equivalent S(2)V3Cu tetrahedra and edges with two equivalent S(4)MgV2Cu tetrahedra.