Li4Fe(OF)2 crystallizes in the monoclinic Cm space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one F(2), and two equivalent F(1) atoms to form distorted LiO2F3 trigonal bipyramids that share corners with two equivalent Li(1)O2F3 trigonal bipyramids,  a cornercorner with one Li(3)O3F trigonal pyramid, corners with four equivalent Li(4)O3F trigonal pyramids, edges with three equivalent Li(2)O2F3 trigonal bipyramids, and edges with two equivalent Li(3)O3F trigonal pyramids. In the second Li site, Li(2) is bonded to one O(1), one O(2), one F(1), and two equivalent F(2) atoms to form LiO2F3 trigonal bipyramids that share corners with two equivalent Li(2)O2F3 trigonal bipyramids,  a cornercorner with one Li(4)O3F trigonal pyramid, corners with four equivalent Li(3)O3F trigonal pyramids, edges with three equivalent Li(1)O2F3 trigonal bipyramids, and edges with two equivalent Li(4)O3F trigonal pyramids. In the third Li site, Li(3) is bonded to one O(2), two equivalent O(1), and one F(1) atom to form distorted LiO3F trigonal pyramids that share  a cornercorner with one Li(1)O2F3 trigonal bipyramid, corners with four equivalent Li(2)O2F3 trigonal bipyramids, corners with two equivalent Li(3)O3F trigonal pyramids, edges with two equivalent Li(1)O2F3 trigonal bipyramids, and edges with two equivalent Li(4)O3F trigonal pyramids. In the fourth Li site, Li(4) is bonded to one O(1), two equivalent O(2), and one F(2) atom to form distorted LiO3F trigonal pyramids that share  a cornercorner with one Li(2)O2F3 trigonal bipyramid, corners with four equivalent Li(1)O2F3 trigonal bipyramids, corners with two equivalent Li(4)O3F trigonal pyramids, edges with two equivalent Li(2)O2F3 trigonal bipyramids, and edges with two equivalent Li(3)O3F trigonal pyramids. Fe(1) is bonded in a square co-planar geometry to one O(1), one O(2), one F(1), and one F(2) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Li(4), two equivalent Li(3), and one Fe(1) atom to form distorted OLi5Fe octahedra that share  a cornercorner with one O(2)Li5Fe octahedra, corners with two equivalent O(1)Li5Fe octahedra, corners with three equivalent F(2)Li4Fe trigonal bipyramids, edges with three equivalent O(2)Li5Fe octahedra,  an edgeedge with one F(2)Li4Fe trigonal bipyramid, and edges with three equivalent F(1)Li4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-39°. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Li(3), two equivalent Li(4), and one Fe(1) atom to form distorted OLi5Fe octahedra that share  a cornercorner with one O(1)Li5Fe octahedra, corners with two equivalent O(2)Li5Fe octahedra, corners with three equivalent F(1)Li4Fe trigonal bipyramids, edges with three equivalent O(1)Li5Fe octahedra,  an edgeedge with one F(1)Li4Fe trigonal bipyramid, and edges with three equivalent F(2)Li4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-39°. There are two inequivalent F sites. In the first F site, F(1) is bonded to one Li(2), one Li(3), two equivalent Li(1), and one Fe(1) atom to form FLi4Fe trigonal bipyramids that share corners with three equivalent O(2)Li5Fe octahedra,  a cornercorner with one F(2)Li4Fe trigonal bipyramid, corners with two equivalent F(1)Li4Fe trigonal bipyramids,  an edgeedge with one O(2)Li5Fe octahedra, edges with three equivalent O(1)Li5Fe octahedra, and edges with two equivalent F(2)Li4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 15-66°. In the second F site, F(2) is bonded to one Li(1), one Li(4), two equivalent Li(2), and one Fe(1) atom to form FLi4Fe trigonal bipyramids that share corners with three equivalent O(1)Li5Fe octahedra,  a cornercorner with one F(1)Li4Fe trigonal bipyramid, corners with two equivalent F(2)Li4Fe trigonal bipyramids,  an edgeedge with one O(1)Li5Fe octahedra, edges with three equivalent O(2)Li5Fe octahedra, and edges with two equivalent F(1)Li4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 15-66°.
Li4Fe(OF)2 crystallizes in the monoclinic Cm space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one F(2), and two equivalent F(1) atoms to form distorted LiO2F3 trigonal bipyramids that share corners with two equivalent Li(1)O2F3 trigonal bipyramids,  a cornercorner with one Li(3)O3F trigonal pyramid, corners with four equivalent Li(4)O3F trigonal pyramids, edges with three equivalent Li(2)O2F3 trigonal bipyramids, and edges with two equivalent Li(3)O3F trigonal pyramids. The Li(1)-O(1) bond length is 2.21 Å. The Li(1)-O(2) bond length is 1.99 Å. The Li(1)-F(2) bond length is 2.07 Å. Both Li(1)-F(1) bond lengths are 2.01 Å. In the second Li site, Li(2) is bonded to one O(1), one O(2), one F(1), and two equivalent F(2) atoms to form LiO2F3 trigonal bipyramids that share corners with two equivalent Li(2)O2F3 trigonal bipyramids,  a cornercorner with one Li(4)O3F trigonal pyramid, corners with four equivalent Li(3)O3F trigonal pyramids, edges with three equivalent Li(1)O2F3 trigonal bipyramids, and edges with two equivalent Li(4)O3F trigonal pyramids. The Li(2)-O(1) bond length is 1.99 Å. The Li(2)-O(2) bond length is 2.19 Å. The Li(2)-F(1) bond length is 2.09 Å. Both Li(2)-F(2) bond lengths are 2.01 Å. In the third Li site, Li(3) is bonded to one O(2), two equivalent O(1), and one F(1) atom to form distorted LiO3F trigonal pyramids that share  a cornercorner with one Li(1)O2F3 trigonal bipyramid, corners with four equivalent Li(2)O2F3 trigonal bipyramids, corners with two equivalent Li(3)O3F trigonal pyramids, edges with two equivalent Li(1)O2F3 trigonal bipyramids, and edges with two equivalent Li(4)O3F trigonal pyramids. The Li(3)-O(2) bond length is 2.09 Å. Both Li(3)-O(1) bond lengths are 1.94 Å. The Li(3)-F(1) bond length is 1.92 Å. In the fourth Li site, Li(4) is bonded to one O(1), two equivalent O(2), and one F(2) atom to form distorted LiO3F trigonal pyramids that share  a cornercorner with one Li(2)O2F3 trigonal bipyramid, corners with four equivalent Li(1)O2F3 trigonal bipyramids, corners with two equivalent Li(4)O3F trigonal pyramids, edges with two equivalent Li(2)O2F3 trigonal bipyramids, and edges with two equivalent Li(3)O3F trigonal pyramids. The Li(4)-O(1) bond length is 2.09 Å. Both Li(4)-O(2) bond lengths are 1.94 Å. The Li(4)-F(2) bond length is 1.92 Å. Fe(1) is bonded in a square co-planar geometry to one O(1), one O(2), one F(1), and one F(2) atom. The Fe(1)-O(1) bond length is 1.91 Å. The Fe(1)-O(2) bond length is 1.92 Å. The Fe(1)-F(1) bond length is 2.16 Å. The Fe(1)-F(2) bond length is 2.16 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Li(4), two equivalent Li(3), and one Fe(1) atom to form distorted OLi5Fe octahedra that share  a cornercorner with one O(2)Li5Fe octahedra, corners with two equivalent O(1)Li5Fe octahedra, corners with three equivalent F(2)Li4Fe trigonal bipyramids, edges with three equivalent O(2)Li5Fe octahedra,  an edgeedge with one F(2)Li4Fe trigonal bipyramid, and edges with three equivalent F(1)Li4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-39°. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Li(3), two equivalent Li(4), and one Fe(1) atom to form distorted OLi5Fe octahedra that share  a cornercorner with one O(1)Li5Fe octahedra, corners with two equivalent O(2)Li5Fe octahedra, corners with three equivalent F(1)Li4Fe trigonal bipyramids, edges with three equivalent O(1)Li5Fe octahedra,  an edgeedge with one F(1)Li4Fe trigonal bipyramid, and edges with three equivalent F(2)Li4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-39°. There are two inequivalent F sites. In the first F site, F(1) is bonded to one Li(2), one Li(3), two equivalent Li(1), and one Fe(1) atom to form FLi4Fe trigonal bipyramids that share corners with three equivalent O(2)Li5Fe octahedra,  a cornercorner with one F(2)Li4Fe trigonal bipyramid, corners with two equivalent F(1)Li4Fe trigonal bipyramids,  an edgeedge with one O(2)Li5Fe octahedra, edges with three equivalent O(1)Li5Fe octahedra, and edges with two equivalent F(2)Li4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 15-66°. In the second F site, F(2) is bonded to one Li(1), one Li(4), two equivalent Li(2), and one Fe(1) atom to form FLi4Fe trigonal bipyramids that share corners with three equivalent O(1)Li5Fe octahedra,  a cornercorner with one F(1)Li4Fe trigonal bipyramid, corners with two equivalent F(2)Li4Fe trigonal bipyramids,  an edgeedge with one O(1)Li5Fe octahedra, edges with three equivalent O(2)Li5Fe octahedra, and edges with two equivalent F(1)Li4Fe trigonal bipyramids. The corner-sharing octahedral tilt angles range from 15-66°.