MgVNiS4 is Spinel-derived structured and crystallizes in the orthorhombic Imma space group. Mg(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form MgS4 tetrahedra that share corners with six equivalent V(1)S6 octahedra and corners with six equivalent Ni(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 57-61°. V(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form VS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent V(1)S6 octahedra, and edges with four equivalent Ni(1)S6 octahedra. Ni(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form NiS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Ni(1)S6 octahedra, and edges with four equivalent V(1)S6 octahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), two equivalent V(1), and one Ni(1) atom to form distorted SMgV2Ni trigonal pyramids that share corners with six equivalent S(2)MgVNi2 tetrahedra, corners with six equivalent S(1)MgV2Ni trigonal pyramids, edges with two equivalent S(2)MgVNi2 tetrahedra, and  an edgeedge with one S(1)MgV2Ni trigonal pyramid. In the second S site, S(2) is bonded to one Mg(1), one V(1), and two equivalent Ni(1) atoms to form distorted SMgVNi2 tetrahedra that share corners with six equivalent S(2)MgVNi2 tetrahedra, corners with six equivalent S(1)MgV2Ni trigonal pyramids,  an edgeedge with one S(2)MgVNi2 tetrahedra, and edges with two equivalent S(1)MgV2Ni trigonal pyramids.
MgVNiS4 is Spinel-derived structured and crystallizes in the orthorhombic Imma space group. Mg(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form MgS4 tetrahedra that share corners with six equivalent V(1)S6 octahedra and corners with six equivalent Ni(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 57-61°. Both Mg(1)-S(1) bond lengths are 2.43 Å. Both Mg(1)-S(2) bond lengths are 2.44 Å. V(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form VS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent V(1)S6 octahedra, and edges with four equivalent Ni(1)S6 octahedra. Both V(1)-S(2) bond lengths are 2.44 Å. All V(1)-S(1) bond lengths are 2.41 Å. Ni(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form NiS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Ni(1)S6 octahedra, and edges with four equivalent V(1)S6 octahedra. Both Ni(1)-S(1) bond lengths are 2.39 Å. All Ni(1)-S(2) bond lengths are 2.35 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), two equivalent V(1), and one Ni(1) atom to form distorted SMgV2Ni trigonal pyramids that share corners with six equivalent S(2)MgVNi2 tetrahedra, corners with six equivalent S(1)MgV2Ni trigonal pyramids, edges with two equivalent S(2)MgVNi2 tetrahedra, and  an edgeedge with one S(1)MgV2Ni trigonal pyramid. In the second S site, S(2) is bonded to one Mg(1), one V(1), and two equivalent Ni(1) atoms to form distorted SMgVNi2 tetrahedra that share corners with six equivalent S(2)MgVNi2 tetrahedra, corners with six equivalent S(1)MgV2Ni trigonal pyramids,  an edgeedge with one S(2)MgVNi2 tetrahedra, and edges with two equivalent S(1)MgV2Ni trigonal pyramids.