Li2Fe3F8 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one F(1), one F(2), one F(3), and one F(6) atom to form LiF4 tetrahedra that share corners with three equivalent Fe(1)F6 octahedra, corners with three equivalent Fe(2)F6 octahedra, and corners with three equivalent Fe(3)F6 octahedra. The corner-sharing octahedral tilt angles range from 49-68°. In the second Li site, Li(2) is bonded to one F(4), one F(5), one F(7), and one F(8) atom to form LiF4 trigonal pyramids that share  a cornercorner with one Fe(2)F6 octahedra,  a cornercorner with one Fe(3)F6 octahedra, corners with three equivalent Fe(1)F6 octahedra,  an edgeedge with one Fe(2)F6 octahedra, and  an edgeedge with one Fe(3)F6 octahedra. The corner-sharing octahedral tilt angles range from 55-66°. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one F(2), one F(4), one F(5), one F(8), and two equivalent F(3) atoms to form FeF6 octahedra that share  a cornercorner with one Fe(2)F6 octahedra, corners with two equivalent Fe(3)F6 octahedra, corners with three equivalent Li(1)F4 tetrahedra, corners with three equivalent Li(2)F4 trigonal pyramids,  an edgeedge with one Fe(1)F6 octahedra, and  an edgeedge with one Fe(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 47-60°. In the second Fe site, Fe(2) is bonded to one F(1), one F(2), one F(5), one F(6), one F(7), and one F(8) atom to form FeF6 octahedra that share  a cornercorner with one Fe(1)F6 octahedra,  a cornercorner with one Fe(3)F6 octahedra, corners with three equivalent Li(1)F4 tetrahedra,  a cornercorner with one Li(2)F4 trigonal pyramid,  an edgeedge with one Fe(1)F6 octahedra, edges with two equivalent Fe(3)F6 octahedra, and  an edgeedge with one Li(2)F4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 48-60°. In the third Fe site, Fe(3) is bonded to one F(1), one F(4), one F(7), one F(8), and two equivalent F(6) atoms to form FeF6 octahedra that share  a cornercorner with one Fe(2)F6 octahedra, corners with two equivalent Fe(1)F6 octahedra, corners with three equivalent Li(1)F4 tetrahedra,  a cornercorner with one Li(2)F4 trigonal pyramid,  an edgeedge with one Fe(3)F6 octahedra, edges with two equivalent Fe(2)F6 octahedra, and  an edgeedge with one Li(2)F4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 47-52°. There are eight inequivalent F sites. In the first F site, F(8) is bonded to one Li(2), one Fe(1), one Fe(2), and one Fe(3) atom to form a mixture of distorted edge and corner-sharing FLiFe3 trigonal pyramids. In the second F site, F(1) is bonded in a trigonal planar geometry to one Li(1), one Fe(2), and one Fe(3) atom. In the third F site, F(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one Fe(2) atom. In the fourth F site, F(3) is bonded in a distorted trigonal planar geometry to one Li(1) and two equivalent Fe(1) atoms. In the fifth F site, F(4) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Fe(3) atom. In the sixth F site, F(5) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Fe(2) atom. In the seventh F site, F(6) is bonded to one Li(1), one Fe(2), and two equivalent Fe(3) atoms to form a mixture of distorted edge and corner-sharing FLiFe3 tetrahedra. In the eighth F site, F(7) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(2), and one Fe(3) atom.
Li2Fe3F8 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one F(1), one F(2), one F(3), and one F(6) atom to form LiF4 tetrahedra that share corners with three equivalent Fe(1)F6 octahedra, corners with three equivalent Fe(2)F6 octahedra, and corners with three equivalent Fe(3)F6 octahedra. The corner-sharing octahedral tilt angles range from 49-68°. The Li(1)-F(1) bond length is 1.96 Å. The Li(1)-F(2) bond length is 1.92 Å. The Li(1)-F(3) bond length is 1.92 Å. The Li(1)-F(6) bond length is 2.04 Å. In the second Li site, Li(2) is bonded to one F(4), one F(5), one F(7), and one F(8) atom to form LiF4 trigonal pyramids that share  a cornercorner with one Fe(2)F6 octahedra,  a cornercorner with one Fe(3)F6 octahedra, corners with three equivalent Fe(1)F6 octahedra,  an edgeedge with one Fe(2)F6 octahedra, and  an edgeedge with one Fe(3)F6 octahedra. The corner-sharing octahedral tilt angles range from 55-66°. The Li(2)-F(4) bond length is 1.90 Å. The Li(2)-F(5) bond length is 1.85 Å. The Li(2)-F(7) bond length is 1.95 Å. The Li(2)-F(8) bond length is 2.00 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one F(2), one F(4), one F(5), one F(8), and two equivalent F(3) atoms to form FeF6 octahedra that share  a cornercorner with one Fe(2)F6 octahedra, corners with two equivalent Fe(3)F6 octahedra, corners with three equivalent Li(1)F4 tetrahedra, corners with three equivalent Li(2)F4 trigonal pyramids,  an edgeedge with one Fe(1)F6 octahedra, and  an edgeedge with one Fe(2)F6 octahedra. The corner-sharing octahedral tilt angles range from 47-60°. The Fe(1)-F(2) bond length is 2.11 Å. The Fe(1)-F(4) bond length is 2.04 Å. The Fe(1)-F(5) bond length is 2.08 Å. The Fe(1)-F(8) bond length is 2.20 Å. There is one shorter (2.09 Å) and one longer (2.15 Å) Fe(1)-F(3) bond length. In the second Fe site, Fe(2) is bonded to one F(1), one F(2), one F(5), one F(6), one F(7), and one F(8) atom to form FeF6 octahedra that share  a cornercorner with one Fe(1)F6 octahedra,  a cornercorner with one Fe(3)F6 octahedra, corners with three equivalent Li(1)F4 tetrahedra,  a cornercorner with one Li(2)F4 trigonal pyramid,  an edgeedge with one Fe(1)F6 octahedra, edges with two equivalent Fe(3)F6 octahedra, and  an edgeedge with one Li(2)F4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 48-60°. The Fe(2)-F(1) bond length is 2.02 Å. The Fe(2)-F(2) bond length is 2.10 Å. The Fe(2)-F(5) bond length is 2.09 Å. The Fe(2)-F(6) bond length is 2.28 Å. The Fe(2)-F(7) bond length is 2.07 Å. The Fe(2)-F(8) bond length is 2.14 Å. In the third Fe site, Fe(3) is bonded to one F(1), one F(4), one F(7), one F(8), and two equivalent F(6) atoms to form FeF6 octahedra that share  a cornercorner with one Fe(2)F6 octahedra, corners with two equivalent Fe(1)F6 octahedra, corners with three equivalent Li(1)F4 tetrahedra,  a cornercorner with one Li(2)F4 trigonal pyramid,  an edgeedge with one Fe(3)F6 octahedra, edges with two equivalent Fe(2)F6 octahedra, and  an edgeedge with one Li(2)F4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 47-52°. The Fe(3)-F(1) bond length is 2.10 Å. The Fe(3)-F(4) bond length is 2.06 Å. The Fe(3)-F(7) bond length is 2.03 Å. The Fe(3)-F(8) bond length is 2.22 Å. There is one shorter (2.15 Å) and one longer (2.19 Å) Fe(3)-F(6) bond length. There are eight inequivalent F sites. In the first F site, F(8) is bonded to one Li(2), one Fe(1), one Fe(2), and one Fe(3) atom to form a mixture of distorted edge and corner-sharing FLiFe3 trigonal pyramids. In the second F site, F(1) is bonded in a trigonal planar geometry to one Li(1), one Fe(2), and one Fe(3) atom. In the third F site, F(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one Fe(2) atom. In the fourth F site, F(3) is bonded in a distorted trigonal planar geometry to one Li(1) and two equivalent Fe(1) atoms. In the fifth F site, F(4) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Fe(3) atom. In the sixth F site, F(5) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Fe(2) atom. In the seventh F site, F(6) is bonded to one Li(1), one Fe(2), and two equivalent Fe(3) atoms to form a mixture of distorted edge and corner-sharing FLiFe3 tetrahedra. In the eighth F site, F(7) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(2), and one Fe(3) atom.