MgMnGaS4 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 Mn(1)S6 octahedra and corners with six equivalent Ga(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-60°. Mn(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form MnS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Mn(1)S6 octahedra, and edges with four equivalent Ga(1)S6 octahedra. Ga(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form GaS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Ga(1)S6 octahedra, and edges with four equivalent Mn(1)S6 octahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), two equivalent Mn(1), and one Ga(1) atom to form distorted SMgMn2Ga trigonal pyramids that share corners with six equivalent S(1)MgMn2Ga trigonal pyramids, corners with six equivalent S(2)MgMnGa2 trigonal pyramids,  an edgeedge with one S(1)MgMn2Ga trigonal pyramid, and edges with two equivalent S(2)MgMnGa2 trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), one Mn(1), and two equivalent Ga(1) atoms to form distorted SMgMnGa2 trigonal pyramids that share corners with six equivalent S(1)MgMn2Ga trigonal pyramids, corners with six equivalent S(2)MgMnGa2 trigonal pyramids,  an edgeedge with one S(2)MgMnGa2 trigonal pyramid, and edges with two equivalent S(1)MgMn2Ga trigonal pyramids.
MgMnGaS4 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 Mn(1)S6 octahedra and corners with six equivalent Ga(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 58-60°. Both Mg(1)-S(1) bond lengths are 2.44 Å. Both Mg(1)-S(2) bond lengths are 2.45 Å. Mn(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form MnS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Mn(1)S6 octahedra, and edges with four equivalent Ga(1)S6 octahedra. Both Mn(1)-S(2) bond lengths are 2.42 Å. All Mn(1)-S(1) bond lengths are 2.48 Å. Ga(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form GaS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent Ga(1)S6 octahedra, and edges with four equivalent Mn(1)S6 octahedra. Both Ga(1)-S(1) bond lengths are 2.46 Å. All Ga(1)-S(2) bond lengths are 2.49 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), two equivalent Mn(1), and one Ga(1) atom to form distorted SMgMn2Ga trigonal pyramids that share corners with six equivalent S(1)MgMn2Ga trigonal pyramids, corners with six equivalent S(2)MgMnGa2 trigonal pyramids,  an edgeedge with one S(1)MgMn2Ga trigonal pyramid, and edges with two equivalent S(2)MgMnGa2 trigonal pyramids. In the second S site, S(2) is bonded to one Mg(1), one Mn(1), and two equivalent Ga(1) atoms to form distorted SMgMnGa2 trigonal pyramids that share corners with six equivalent S(1)MgMn2Ga trigonal pyramids, corners with six equivalent S(2)MgMnGa2 trigonal pyramids,  an edgeedge with one S(2)MgMnGa2 trigonal pyramid, and edges with two equivalent S(1)MgMn2Ga trigonal pyramids.