Li2FeF4 crystallizes in the trigonal R-3 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one F(2), one F(4), and two equivalent F(1) atoms to form LiF4 tetrahedra that share corners with two equivalent Li(1)F4 tetrahedra, corners with two equivalent Li(2)F4 tetrahedra, and corners with four equivalent Fe(1)F5 trigonal bipyramids. In the second Li site, Li(2) is bonded to one F(2), one F(4), and two equivalent F(3) atoms to form LiF4 tetrahedra that share corners with two equivalent Li(1)F4 tetrahedra, corners with two equivalent Li(2)F4 tetrahedra, corners with four equivalent Fe(1)F5 trigonal bipyramids, and  an edgeedge with one Fe(1)F5 trigonal bipyramid. Fe(1) is bonded to one F(1), one F(2), one F(4), and two equivalent F(3) atoms to form distorted FeF5 trigonal bipyramids that share corners with four equivalent Li(1)F4 tetrahedra, corners with four equivalent Li(2)F4 tetrahedra,  an edgeedge with one Li(2)F4 tetrahedra, and  an edgeedge with one Fe(1)F5 trigonal bipyramid. There are four inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to two equivalent Li(1) and one Fe(1) atom. In the second F site, F(2) is bonded in a trigonal planar geometry to one Li(1), one Li(2), and one Fe(1) atom. In the third F site, F(3) is bonded to two equivalent Li(2) and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing FLi2Fe2 tetrahedra. In the fourth F site, F(4) is bonded in a trigonal planar geometry to one Li(1), one Li(2), and one Fe(1) atom.
Li2FeF4 crystallizes in the trigonal R-3 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one F(2), one F(4), and two equivalent F(1) atoms to form LiF4 tetrahedra that share corners with two equivalent Li(1)F4 tetrahedra, corners with two equivalent Li(2)F4 tetrahedra, and corners with four equivalent Fe(1)F5 trigonal bipyramids. The Li(1)-F(2) bond length is 1.93 Å. The Li(1)-F(4) bond length is 1.89 Å. There is one shorter (1.89 Å) and one longer (1.90 Å) Li(1)-F(1) bond length. In the second Li site, Li(2) is bonded to one F(2), one F(4), and two equivalent F(3) atoms to form LiF4 tetrahedra that share corners with two equivalent Li(1)F4 tetrahedra, corners with two equivalent Li(2)F4 tetrahedra, corners with four equivalent Fe(1)F5 trigonal bipyramids, and  an edgeedge with one Fe(1)F5 trigonal bipyramid. The Li(2)-F(2) bond length is 1.92 Å. The Li(2)-F(4) bond length is 1.86 Å. There is one shorter (1.94 Å) and one longer (2.02 Å) Li(2)-F(3) bond length. Fe(1) is bonded to one F(1), one F(2), one F(4), and two equivalent F(3) atoms to form distorted FeF5 trigonal bipyramids that share corners with four equivalent Li(1)F4 tetrahedra, corners with four equivalent Li(2)F4 tetrahedra,  an edgeedge with one Li(2)F4 tetrahedra, and  an edgeedge with one Fe(1)F5 trigonal bipyramid. The Fe(1)-F(1) bond length is 1.94 Å. The Fe(1)-F(2) bond length is 1.96 Å. The Fe(1)-F(4) bond length is 2.06 Å. There is one shorter (2.10 Å) and one longer (2.40 Å) Fe(1)-F(3) bond length. There are four inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to two equivalent Li(1) and one Fe(1) atom. In the second F site, F(2) is bonded in a trigonal planar geometry to one Li(1), one Li(2), and one Fe(1) atom. In the third F site, F(3) is bonded to two equivalent Li(2) and two equivalent Fe(1) atoms to form a mixture of distorted edge and corner-sharing FLi2Fe2 tetrahedra. In the fourth F site, F(4) is bonded in a trigonal planar geometry to one Li(1), one Li(2), and one Fe(1) atom.