MgAl2S4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to one S(1), one S(2), and four equivalent S(3) atoms to form MgS6 octahedra that share corners with four equivalent Mg(1)S6 octahedra, corners with four equivalent Al(2)S6 octahedra, corners with four equivalent Al(1)S4 tetrahedra, edges with two equivalent Al(2)S6 octahedra, and  an edgeedge with one Al(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-53°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one S(1), one S(2), and two equivalent S(3) atoms to form AlS4 tetrahedra that share corners with two equivalent Al(2)S6 octahedra, corners with four equivalent Mg(1)S6 octahedra,  an edgeedge with one Mg(1)S6 octahedra, and edges with two equivalent Al(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 59-67°. In the second Al site, Al(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form AlS6 octahedra that share corners with four equivalent Mg(1)S6 octahedra, corners with two equivalent Al(1)S4 tetrahedra, edges with two equivalent Mg(1)S6 octahedra, edges with two equivalent Al(2)S6 octahedra, and edges with two equivalent Al(1)S4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one Al(1), and two equivalent Al(2) atoms to form distorted corner-sharing SMgAl3 trigonal pyramids. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Al(1), and two equivalent Al(2) atoms. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1), one Al(1), and one Al(2) atom.
MgAl2S4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to one S(1), one S(2), and four equivalent S(3) atoms to form MgS6 octahedra that share corners with four equivalent Mg(1)S6 octahedra, corners with four equivalent Al(2)S6 octahedra, corners with four equivalent Al(1)S4 tetrahedra, edges with two equivalent Al(2)S6 octahedra, and  an edgeedge with one Al(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-53°. The Mg(1)-S(1) bond length is 2.59 Å. The Mg(1)-S(2) bond length is 2.59 Å. There are two shorter (2.59 Å) and two longer (2.64 Å) Mg(1)-S(3) bond lengths. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one S(1), one S(2), and two equivalent S(3) atoms to form AlS4 tetrahedra that share corners with two equivalent Al(2)S6 octahedra, corners with four equivalent Mg(1)S6 octahedra,  an edgeedge with one Mg(1)S6 octahedra, and edges with two equivalent Al(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 59-67°. The Al(1)-S(1) bond length is 2.23 Å. The Al(1)-S(2) bond length is 2.26 Å. Both Al(1)-S(3) bond lengths are 2.23 Å. In the second Al site, Al(2) is bonded to two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms to form AlS6 octahedra that share corners with four equivalent Mg(1)S6 octahedra, corners with two equivalent Al(1)S4 tetrahedra, edges with two equivalent Mg(1)S6 octahedra, edges with two equivalent Al(2)S6 octahedra, and edges with two equivalent Al(1)S4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. Both Al(2)-S(1) bond lengths are 2.45 Å. Both Al(2)-S(2) bond lengths are 2.44 Å. Both Al(2)-S(3) bond lengths are 2.44 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded to one Mg(1), one Al(1), and two equivalent Al(2) atoms to form distorted corner-sharing SMgAl3 trigonal pyramids. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Al(1), and two equivalent Al(2) atoms. In the third S site, S(3) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1), one Al(1), and one Al(2) atom.