Mg2VMo3S8 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 V(1)S6 octahedra and corners with nine equivalent Mo(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. V(1) is bonded to six equivalent S(2) atoms to form VS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra and edges with six equivalent Mo(1)S6 octahedra. Mo(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form MoS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent V(1)S6 octahedra, and edges with four equivalent Mo(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 Mo(1) atoms to form distorted SMgMo3 trigonal pyramids that share corners with three equivalent S(1)MgMo3 trigonal pyramids, corners with nine equivalent S(2)MgVMo2 trigonal pyramids, and edges with three equivalent S(2)MgVMo2 trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), one V(1), and two equivalent Mo(1) atoms to form distorted SMgVMo2 trigonal pyramids that share corners with three equivalent S(1)MgMo3 trigonal pyramids, corners with nine equivalent S(2)MgVMo2 trigonal pyramids,  an edgeedge with one S(1)MgMo3 trigonal pyramid, and edges with two equivalent S(2)MgVMo2 trigonal pyramids.
Mg2VMo3S8 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 V(1)S6 octahedra and corners with nine equivalent Mo(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 57-60°. The Mg(1)-S(1) bond length is 2.48 Å. All Mg(1)-S(2) bond lengths are 2.47 Å. V(1) is bonded to six equivalent S(2) atoms to form VS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra and edges with six equivalent Mo(1)S6 octahedra. All V(1)-S(2) bond lengths are 2.48 Å. Mo(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form MoS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent V(1)S6 octahedra, and edges with four equivalent Mo(1)S6 octahedra. Both Mo(1)-S(1) bond lengths are 2.51 Å. All Mo(1)-S(2) bond lengths are 2.52 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1) and three equivalent Mo(1) atoms to form distorted SMgMo3 trigonal pyramids that share corners with three equivalent S(1)MgMo3 trigonal pyramids, corners with nine equivalent S(2)MgVMo2 trigonal pyramids, and edges with three equivalent S(2)MgVMo2 trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), one V(1), and two equivalent Mo(1) atoms to form distorted SMgVMo2 trigonal pyramids that share corners with three equivalent S(1)MgMo3 trigonal pyramids, corners with nine equivalent S(2)MgVMo2 trigonal pyramids,  an edgeedge with one S(1)MgMo3 trigonal pyramid, and edges with two equivalent S(2)MgVMo2 trigonal pyramids.