MgInS3 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form MgS6 octahedra that share corners with eight equivalent In(1)S4 tetrahedra and edges with three equivalent Mg(1)S6 octahedra. In(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form InS4 tetrahedra that share corners with eight equivalent Mg(1)S6 octahedra and  an edgeedge with one In(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 60-68°. There are two inequivalent S sites. In the first S site, S(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Mg(1) and one In(1) atom. In the second S site, S(2) is bonded to two equivalent Mg(1) and two equivalent In(1) atoms to form edge-sharing SMg2In2 tetrahedra.
MgInS3 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form MgS6 octahedra that share corners with eight equivalent In(1)S4 tetrahedra and edges with three equivalent Mg(1)S6 octahedra. Both Mg(1)-S(2) bond lengths are 2.57 Å. All Mg(1)-S(1) bond lengths are 2.63 Å. In(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form InS4 tetrahedra that share corners with eight equivalent Mg(1)S6 octahedra and  an edgeedge with one In(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 60-68°. Both In(1)-S(1) bond lengths are 2.48 Å. There is one shorter (2.50 Å) and one longer (2.51 Å) In(1)-S(2) bond length. There are two inequivalent S sites. In the first S site, S(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Mg(1) and one In(1) atom. In the second S site, S(2) is bonded to two equivalent Mg(1) and two equivalent In(1) atoms to form edge-sharing SMg2In2 tetrahedra.