Mg2V3AlS8 is Spinel-derived structured and crystallizes in the trigonal R-3m space group. Mg(1) is bonded to one S(1) and three equivalent S(2) atoms to form MgS4 tetrahedra that share corners with three equivalent Al(1)S6 octahedra and corners with nine equivalent V(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-59°. 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 Al(1)S6 octahedra, and edges with four equivalent V(1)S6 octahedra. Al(1) is bonded to six equivalent S(2) atoms to form AlS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra and edges with six equivalent V(1)S6 octahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1) and three equivalent V(1) atoms to form distorted SMgV3 trigonal pyramids that share corners with three equivalent S(1)MgV3 trigonal pyramids, corners with nine equivalent S(2)MgAlV2 trigonal pyramids, and edges with three equivalent S(2)MgAlV2 trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), two equivalent V(1), and one Al(1) atom to form distorted SMgAlV2 trigonal pyramids that share corners with three equivalent S(1)MgV3 trigonal pyramids, corners with nine equivalent S(2)MgAlV2 trigonal pyramids,  an edgeedge with one S(1)MgV3 trigonal pyramid, and edges with two equivalent S(2)MgAlV2 trigonal pyramids.
Mg2V3AlS8 is Spinel-derived structured and crystallizes in the trigonal R-3m space group. Mg(1) is bonded to one S(1) and three equivalent S(2) atoms to form MgS4 tetrahedra that share corners with three equivalent Al(1)S6 octahedra and corners with nine equivalent V(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-59°. The Mg(1)-S(1) bond length is 2.46 Å. All Mg(1)-S(2) bond lengths are 2.42 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 Al(1)S6 octahedra, and edges with four equivalent V(1)S6 octahedra. Both V(1)-S(1) bond lengths are 2.45 Å. All V(1)-S(2) bond lengths are 2.46 Å. Al(1) is bonded to six equivalent S(2) atoms to form AlS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra and edges with six equivalent V(1)S6 octahedra. All Al(1)-S(2) bond lengths are 2.43 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1) and three equivalent V(1) atoms to form distorted SMgV3 trigonal pyramids that share corners with three equivalent S(1)MgV3 trigonal pyramids, corners with nine equivalent S(2)MgAlV2 trigonal pyramids, and edges with three equivalent S(2)MgAlV2 trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), two equivalent V(1), and one Al(1) atom to form distorted SMgAlV2 trigonal pyramids that share corners with three equivalent S(1)MgV3 trigonal pyramids, corners with nine equivalent S(2)MgAlV2 trigonal pyramids,  an edgeedge with one S(1)MgV3 trigonal pyramid, and edges with two equivalent S(2)MgAlV2 trigonal pyramids.