Li6FeS4 crystallizes in the hexagonal P6_3mc space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one S(2) and three equivalent S(1) atoms to form distorted LiS4 tetrahedra that share corners with two equivalent Fe(1)S4 tetrahedra, corners with eight equivalent Li(1)S4 tetrahedra, and  an edgeedge with one Fe(1)S4 tetrahedra. In the second Li site, Li(2) is bonded in a 3-coordinate geometry to one S(2) and two equivalent S(1) atoms. Fe(1) is bonded to one S(2) and three equivalent S(1) atoms to form distorted FeS4 tetrahedra that share corners with six equivalent Li(1)S4 tetrahedra and edges with three equivalent Li(1)S4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to two equivalent Li(2), three equivalent Li(1), and one Fe(1) atom. In the second S site, S(2) is bonded in a 7-coordinate geometry to three equivalent Li(1), three equivalent Li(2), and one Fe(1) atom.
Li6FeS4 crystallizes in the hexagonal P6_3mc space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one S(2) and three equivalent S(1) atoms to form distorted LiS4 tetrahedra that share corners with two equivalent Fe(1)S4 tetrahedra, corners with eight equivalent Li(1)S4 tetrahedra, and  an edgeedge with one Fe(1)S4 tetrahedra. The Li(1)-S(2) bond length is 2.60 Å. There are two shorter (2.43 Å) and one longer (2.50 Å) Li(1)-S(1) bond length. In the second Li site, Li(2) is bonded in a 3-coordinate geometry to one S(2) and two equivalent S(1) atoms. The Li(2)-S(2) bond length is 2.45 Å. Both Li(2)-S(1) bond lengths are 2.53 Å. Fe(1) is bonded to one S(2) and three equivalent S(1) atoms to form distorted FeS4 tetrahedra that share corners with six equivalent Li(1)S4 tetrahedra and edges with three equivalent Li(1)S4 tetrahedra. The Fe(1)-S(2) bond length is 2.30 Å. All Fe(1)-S(1) bond lengths are 2.29 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to two equivalent Li(2), three equivalent Li(1), and one Fe(1) atom. In the second S site, S(2) is bonded in a 7-coordinate geometry to three equivalent Li(1), three equivalent Li(2), and one Fe(1) atom.