Li3(Fe2S3)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form LiS6 octahedra that share corners with eight equivalent Fe(1)S4 tetrahedra, edges with six equivalent Li(2)S6 octahedra, and edges with four equivalent Fe(1)S4 tetrahedra. In the second Li site, Li(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form LiS6 octahedra that share corners with eight equivalent Fe(1)S4 tetrahedra, edges with three equivalent Li(1)S6 octahedra, edges with three equivalent Li(2)S6 octahedra, and edges with four equivalent Fe(1)S4 tetrahedra. Fe(1) is bonded to one S(1) and three equivalent S(2) atoms to form FeS4 tetrahedra that share corners with two equivalent Li(1)S6 octahedra, corners with four equivalent Li(2)S6 octahedra, corners with three equivalent Fe(1)S4 tetrahedra,  an edgeedge with one Li(1)S6 octahedra, edges with two equivalent Li(2)S6 octahedra, and edges with two equivalent Fe(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-57°. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Li(1), two equivalent Li(2), and two equivalent Fe(1) atoms to form SLi3Fe2 square pyramids that share corners with six equivalent S(2)Li3Fe3 octahedra,  a cornercorner with one S(1)Li3Fe2 square pyramid, edges with six equivalent S(2)Li3Fe3 octahedra, and  an edgeedge with one S(1)Li3Fe2 square pyramid. The corner-sharing octahedral tilt angles range from 7-84°. In the second S site, S(2) is bonded to one Li(1), two equivalent Li(2), and three equivalent Fe(1) atoms to form distorted SLi3Fe3 octahedra that share corners with three equivalent S(2)Li3Fe3 octahedra, corners with three equivalent S(1)Li3Fe2 square pyramids, edges with six equivalent S(2)Li3Fe3 octahedra, and edges with three equivalent S(1)Li3Fe2 square pyramids. The corner-sharing octahedral tilt angles range from 0-88°.
Li3(Fe2S3)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form LiS6 octahedra that share corners with eight equivalent Fe(1)S4 tetrahedra, edges with six equivalent Li(2)S6 octahedra, and edges with four equivalent Fe(1)S4 tetrahedra. Both Li(1)-S(1) bond lengths are 2.51 Å. All Li(1)-S(2) bond lengths are 2.71 Å. In the second Li site, Li(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form LiS6 octahedra that share corners with eight equivalent Fe(1)S4 tetrahedra, edges with three equivalent Li(1)S6 octahedra, edges with three equivalent Li(2)S6 octahedra, and edges with four equivalent Fe(1)S4 tetrahedra. Both Li(2)-S(1) bond lengths are 2.52 Å. All Li(2)-S(2) bond lengths are 2.74 Å. Fe(1) is bonded to one S(1) and three equivalent S(2) atoms to form FeS4 tetrahedra that share corners with two equivalent Li(1)S6 octahedra, corners with four equivalent Li(2)S6 octahedra, corners with three equivalent Fe(1)S4 tetrahedra,  an edgeedge with one Li(1)S6 octahedra, edges with two equivalent Li(2)S6 octahedra, and edges with two equivalent Fe(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-57°. The Fe(1)-S(1) bond length is 2.26 Å. There are a spread of Fe(1)-S(2) bond distances ranging from 2.21-2.27 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Li(1), two equivalent Li(2), and two equivalent Fe(1) atoms to form SLi3Fe2 square pyramids that share corners with six equivalent S(2)Li3Fe3 octahedra,  a cornercorner with one S(1)Li3Fe2 square pyramid, edges with six equivalent S(2)Li3Fe3 octahedra, and  an edgeedge with one S(1)Li3Fe2 square pyramid. The corner-sharing octahedral tilt angles range from 7-84°. In the second S site, S(2) is bonded to one Li(1), two equivalent Li(2), and three equivalent Fe(1) atoms to form distorted SLi3Fe3 octahedra that share corners with three equivalent S(2)Li3Fe3 octahedra, corners with three equivalent S(1)Li3Fe2 square pyramids, edges with six equivalent S(2)Li3Fe3 octahedra, and edges with three equivalent S(1)Li3Fe2 square pyramids. The corner-sharing octahedral tilt angles range from 0-88°.