MgHoS3 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 Ho(1)S4 tetrahedra and edges with three equivalent Mg(1)S6 octahedra. Ho(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form HoS4 tetrahedra that share corners with eight equivalent Mg(1)S6 octahedra and  an edgeedge with one Ho(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-73°. There are two inequivalent S sites. In the first S site, S(1) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one Ho(1) atom. In the second S site, S(2) is bonded to two equivalent Mg(1) and two equivalent Ho(1) atoms to form edge-sharing SHo2Mg2 tetrahedra.
MgHoS3 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 Ho(1)S4 tetrahedra and edges with three equivalent Mg(1)S6 octahedra. Both Mg(1)-S(2) bond lengths are 2.53 Å. There are two shorter (2.55 Å) and two longer (2.82 Å) Mg(1)-S(1) bond lengths. Ho(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form HoS4 tetrahedra that share corners with eight equivalent Mg(1)S6 octahedra and  an edgeedge with one Ho(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-73°. Both Ho(1)-S(1) bond lengths are 2.58 Å. Both Ho(1)-S(2) bond lengths are 2.59 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one Ho(1) atom. In the second S site, S(2) is bonded to two equivalent Mg(1) and two equivalent Ho(1) atoms to form edge-sharing SHo2Mg2 tetrahedra.