Mg2VCo3S8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form MgS4 tetrahedra that share corners with three equivalent V(1)S6 octahedra, corners with three equivalent Co(1)S6 octahedra, and corners with six equivalent Co(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 59-63°. V(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form VS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Co(1)S6 octahedra, and edges with four equivalent Co(2)S6 octahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent S(3) and four equivalent S(2) atoms to form CoS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent V(1)S6 octahedra, and edges with four equivalent Co(2)S6 octahedra. In the second Co site, Co(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form CoS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent V(1)S6 octahedra, edges with two equivalent Co(1)S6 octahedra, and edges with two equivalent Co(2)S6 octahedra. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one V(1), and two equivalent Co(2) atoms to form distorted SMgVCo2 tetrahedra that share corners with three equivalent S(3)MgCo3 tetrahedra, corners with three equivalent S(1)MgVCo2 tetrahedra, corners with six equivalent S(2)MgVCo2 tetrahedra,  an edgeedge with one S(3)MgCo3 tetrahedra, and edges with two equivalent S(2)MgVCo2 tetrahedra. In the second S site, S(2) is bonded to one Mg(1), one V(1), one Co(1), and one Co(2) atom to form distorted SMgVCo2 tetrahedra that share corners with three equivalent S(3)MgCo3 tetrahedra, corners with three equivalent S(1)MgVCo2 tetrahedra, corners with six equivalent S(2)MgVCo2 tetrahedra,  an edgeedge with one S(3)MgCo3 tetrahedra,  an edgeedge with one S(1)MgVCo2 tetrahedra, and  an edgeedge with one S(2)MgVCo2 tetrahedra. In the third S site, S(3) is bonded to one Mg(1), one Co(1), and two equivalent Co(2) atoms to form SMgCo3 tetrahedra that share corners with three equivalent S(3)MgCo3 tetrahedra, corners with three equivalent S(1)MgVCo2 tetrahedra, corners with six equivalent S(2)MgVCo2 tetrahedra,  an edgeedge with one S(1)MgVCo2 tetrahedra, and edges with two equivalent S(2)MgVCo2 tetrahedra.
Mg2VCo3S8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to one S(1), one S(3), and two equivalent S(2) atoms to form MgS4 tetrahedra that share corners with three equivalent V(1)S6 octahedra, corners with three equivalent Co(1)S6 octahedra, and corners with six equivalent Co(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 59-63°. The Mg(1)-S(1) bond length is 2.43 Å. The Mg(1)-S(3) bond length is 2.47 Å. Both Mg(1)-S(2) bond lengths are 2.43 Å. V(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form VS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Co(1)S6 octahedra, and edges with four equivalent Co(2)S6 octahedra. Both V(1)-S(1) bond lengths are 2.41 Å. All V(1)-S(2) bond lengths are 2.40 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent S(3) and four equivalent S(2) atoms to form CoS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent V(1)S6 octahedra, and edges with four equivalent Co(2)S6 octahedra. Both Co(1)-S(3) bond lengths are 2.31 Å. All Co(1)-S(2) bond lengths are 2.30 Å. In the second Co site, Co(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form CoS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent V(1)S6 octahedra, edges with two equivalent Co(1)S6 octahedra, and edges with two equivalent Co(2)S6 octahedra. Both Co(2)-S(1) bond lengths are 2.30 Å. Both Co(2)-S(2) bond lengths are 2.30 Å. Both Co(2)-S(3) bond lengths are 2.31 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one V(1), and two equivalent Co(2) atoms to form distorted SMgVCo2 tetrahedra that share corners with three equivalent S(3)MgCo3 tetrahedra, corners with three equivalent S(1)MgVCo2 tetrahedra, corners with six equivalent S(2)MgVCo2 tetrahedra,  an edgeedge with one S(3)MgCo3 tetrahedra, and edges with two equivalent S(2)MgVCo2 tetrahedra. In the second S site, S(2) is bonded to one Mg(1), one V(1), one Co(1), and one Co(2) atom to form distorted SMgVCo2 tetrahedra that share corners with three equivalent S(3)MgCo3 tetrahedra, corners with three equivalent S(1)MgVCo2 tetrahedra, corners with six equivalent S(2)MgVCo2 tetrahedra,  an edgeedge with one S(3)MgCo3 tetrahedra,  an edgeedge with one S(1)MgVCo2 tetrahedra, and  an edgeedge with one S(2)MgVCo2 tetrahedra. In the third S site, S(3) is bonded to one Mg(1), one Co(1), and two equivalent Co(2) atoms to form SMgCo3 tetrahedra that share corners with three equivalent S(3)MgCo3 tetrahedra, corners with three equivalent S(1)MgVCo2 tetrahedra, corners with six equivalent S(2)MgVCo2 tetrahedra,  an edgeedge with one S(1)MgVCo2 tetrahedra, and edges with two equivalent S(2)MgVCo2 tetrahedra.