Li5FeS4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form distorted LiS4 tetrahedra that share corners with two equivalent Li(2)S4 tetrahedra, corners with two equivalent Fe(1)S4 tetrahedra, corners with eight equivalent Li(1)S4 tetrahedra,  an edgeedge with one Li(2)S4 tetrahedra,  an edgeedge with one Fe(1)S4 tetrahedra, and edges with two equivalent Li(1)S4 tetrahedra. In the second Li site, Li(2) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form LiS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra, corners with eight equivalent Li(1)S4 tetrahedra, and edges with four equivalent Li(1)S4 tetrahedra. Fe(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form FeS4 tetrahedra that share corners with four equivalent Li(2)S4 tetrahedra, corners with eight equivalent Li(1)S4 tetrahedra, and edges with four equivalent Li(1)S4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Li(2), four equivalent Li(1), and one Fe(1) atom to form a mixture of distorted corner and edge-sharing SLi5Fe octahedra. The corner-sharing octahedral tilt angles range from 64-67°. In the second S site, S(2) is bonded in a 6-coordinate geometry to one Li(2), four equivalent Li(1), and one Fe(1) atom.
Li5FeS4 crystallizes in the orthorhombic Pmmn space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form distorted LiS4 tetrahedra that share corners with two equivalent Li(2)S4 tetrahedra, corners with two equivalent Fe(1)S4 tetrahedra, corners with eight equivalent Li(1)S4 tetrahedra,  an edgeedge with one Li(2)S4 tetrahedra,  an edgeedge with one Fe(1)S4 tetrahedra, and edges with two equivalent Li(1)S4 tetrahedra. Both Li(1)-S(1) bond lengths are 2.48 Å. There is one shorter (2.45 Å) and one longer (2.54 Å) Li(1)-S(2) bond length. In the second Li site, Li(2) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form LiS4 tetrahedra that share corners with four equivalent Fe(1)S4 tetrahedra, corners with eight equivalent Li(1)S4 tetrahedra, and edges with four equivalent Li(1)S4 tetrahedra. Both Li(2)-S(1) bond lengths are 2.44 Å. Both Li(2)-S(2) bond lengths are 2.45 Å. Fe(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form FeS4 tetrahedra that share corners with four equivalent Li(2)S4 tetrahedra, corners with eight equivalent Li(1)S4 tetrahedra, and edges with four equivalent Li(1)S4 tetrahedra. Both Fe(1)-S(1) bond lengths are 2.27 Å. Both Fe(1)-S(2) bond lengths are 2.29 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Li(2), four equivalent Li(1), and one Fe(1) atom to form a mixture of distorted corner and edge-sharing SLi5Fe octahedra. The corner-sharing octahedral tilt angles range from 64-67°. In the second S site, S(2) is bonded in a 6-coordinate geometry to one Li(2), four equivalent Li(1), and one Fe(1) atom.