Mg2Sm3WS8 is Spinel-derived structured and crystallizes in the trigonal R-3m space group. Mg(1) is bonded to one S(2) and three equivalent S(1) atoms to form MgS4 tetrahedra that share corners with three equivalent W(1)S6 octahedra and corners with nine equivalent Sm(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-60°. Sm(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form SmS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent W(1)S6 octahedra, and edges with four equivalent Sm(1)S6 octahedra. W(1) is bonded to six equivalent S(1) atoms to form WS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra and edges with six equivalent Sm(1)S6 octahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Sm(1), and one W(1) atom. In the second S site, S(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1) and three equivalent Sm(1) atoms.
Mg2Sm3WS8 is Spinel-derived structured and crystallizes in the trigonal R-3m space group. Mg(1) is bonded to one S(2) and three equivalent S(1) atoms to form MgS4 tetrahedra that share corners with three equivalent W(1)S6 octahedra and corners with nine equivalent Sm(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-60°. The Mg(1)-S(2) bond length is 2.41 Å. All Mg(1)-S(1) bond lengths are 2.54 Å. Sm(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form SmS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra, edges with two equivalent W(1)S6 octahedra, and edges with four equivalent Sm(1)S6 octahedra. Both Sm(1)-S(2) bond lengths are 2.74 Å. All Sm(1)-S(1) bond lengths are 2.80 Å. W(1) is bonded to six equivalent S(1) atoms to form WS6 octahedra that share corners with six equivalent Mg(1)S4 tetrahedra and edges with six equivalent Sm(1)S6 octahedra. All W(1)-S(1) bond lengths are 2.57 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Sm(1), and one W(1) atom. In the second S site, S(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1) and three equivalent Sm(1) atoms.