Fe10O9F11 is Hydrophilite-derived structured and crystallizes in the monoclinic Pm space group. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), one O(6), two equivalent F(1), and two equivalent F(4) atoms to form FeO2F4 octahedra that share corners with eight equivalent Fe(4)O3F3 octahedra and edges with two equivalent Fe(2)O2F4 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. In the second Fe site, Fe(2) is bonded to one O(1), one O(4), one F(1), one F(2), one F(4), and one F(6) atom to form FeO2F4 octahedra that share corners with four equivalent Fe(4)O3F3 octahedra, corners with four equivalent Fe(6)O3F3 octahedra,  an edgeedge with one Fe(1)O2F4 octahedra, and  an edgeedge with one Fe(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-61°. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(5), one F(3), one F(5), and one F(6) atom to form FeO3F3 octahedra that share corners with four equivalent Fe(5)O3F3 octahedra, corners with four equivalent Fe(6)O3F3 octahedra,  an edgeedge with one Fe(2)O2F4 octahedra, and  an edgeedge with one Fe(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 43-55°. In the fourth Fe site, Fe(4) is bonded to one O(3), one O(4), one O(6), one F(1), one F(2), and one F(4) atom to form FeO3F3 octahedra that share corners with four equivalent Fe(1)O2F4 octahedra, corners with four equivalent Fe(2)O2F4 octahedra,  an edgeedge with one Fe(4)O3F3 octahedra, and  an edgeedge with one Fe(6)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-52°. In the fifth Fe site, Fe(5) is bonded to one O(2), two equivalent O(5), one F(5), and two equivalent F(3) atoms to form a mixture of edge and corner-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 46-55°. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(4), one O(5), one F(2), one F(3), and one F(6) atom to form FeO3F3 octahedra that share corners with four equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(3)O3F3 octahedra,  an edgeedge with one Fe(4)O3F3 octahedra, and  an edgeedge with one Fe(5)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 43-61°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(6) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(5) and two equivalent Fe(3) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(1) and two equivalent Fe(4) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(3), one Fe(5), and one Fe(6) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(4) atoms. There are six inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(4) atom. In the second F site, F(2) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Fe(3), one Fe(5), and one Fe(6) atom. In the fourth F site, F(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(4) atom. In the fifth F site, F(5) is bonded in a distorted T-shaped geometry to one Fe(5) and two equivalent Fe(3) atoms. In the sixth F site, F(6) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(3), and one Fe(6) atom.
Fe10O9F11 is Hydrophilite-derived structured and crystallizes in the monoclinic Pm space group. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), one O(6), two equivalent F(1), and two equivalent F(4) atoms to form FeO2F4 octahedra that share corners with eight equivalent Fe(4)O3F3 octahedra and edges with two equivalent Fe(2)O2F4 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. The Fe(1)-O(3) bond length is 1.99 Å. The Fe(1)-O(6) bond length is 1.95 Å. Both Fe(1)-F(1) bond lengths are 2.04 Å. Both Fe(1)-F(4) bond lengths are 2.04 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(4), one F(1), one F(2), one F(4), and one F(6) atom to form FeO2F4 octahedra that share corners with four equivalent Fe(4)O3F3 octahedra, corners with four equivalent Fe(6)O3F3 octahedra,  an edgeedge with one Fe(1)O2F4 octahedra, and  an edgeedge with one Fe(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-61°. The Fe(2)-O(1) bond length is 1.95 Å. The Fe(2)-O(4) bond length is 1.96 Å. The Fe(2)-F(1) bond length is 2.13 Å. The Fe(2)-F(2) bond length is 2.10 Å. The Fe(2)-F(4) bond length is 2.16 Å. The Fe(2)-F(6) bond length is 2.06 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(5), one F(3), one F(5), and one F(6) atom to form FeO3F3 octahedra that share corners with four equivalent Fe(5)O3F3 octahedra, corners with four equivalent Fe(6)O3F3 octahedra,  an edgeedge with one Fe(2)O2F4 octahedra, and  an edgeedge with one Fe(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 43-55°. The Fe(3)-O(1) bond length is 1.94 Å. The Fe(3)-O(2) bond length is 1.94 Å. The Fe(3)-O(5) bond length is 1.94 Å. The Fe(3)-F(3) bond length is 2.11 Å. The Fe(3)-F(5) bond length is 2.16 Å. The Fe(3)-F(6) bond length is 2.20 Å. In the fourth Fe site, Fe(4) is bonded to one O(3), one O(4), one O(6), one F(1), one F(2), and one F(4) atom to form FeO3F3 octahedra that share corners with four equivalent Fe(1)O2F4 octahedra, corners with four equivalent Fe(2)O2F4 octahedra,  an edgeedge with one Fe(4)O3F3 octahedra, and  an edgeedge with one Fe(6)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-52°. The Fe(4)-O(3) bond length is 1.96 Å. The Fe(4)-O(4) bond length is 1.94 Å. The Fe(4)-O(6) bond length is 2.01 Å. The Fe(4)-F(1) bond length is 2.09 Å. The Fe(4)-F(2) bond length is 2.13 Å. The Fe(4)-F(4) bond length is 2.09 Å. In the fifth Fe site, Fe(5) is bonded to one O(2), two equivalent O(5), one F(5), and two equivalent F(3) atoms to form a mixture of edge and corner-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 46-55°. The Fe(5)-O(2) bond length is 1.96 Å. Both Fe(5)-O(5) bond lengths are 1.93 Å. The Fe(5)-F(5) bond length is 2.22 Å. Both Fe(5)-F(3) bond lengths are 2.15 Å. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(4), one O(5), one F(2), one F(3), and one F(6) atom to form FeO3F3 octahedra that share corners with four equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(3)O3F3 octahedra,  an edgeedge with one Fe(4)O3F3 octahedra, and  an edgeedge with one Fe(5)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 43-61°. The Fe(6)-O(1) bond length is 1.93 Å. The Fe(6)-O(4) bond length is 1.94 Å. The Fe(6)-O(5) bond length is 1.94 Å. The Fe(6)-F(2) bond length is 2.18 Å. The Fe(6)-F(3) bond length is 2.15 Å. The Fe(6)-F(6) bond length is 2.20 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(6) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(5) and two equivalent Fe(3) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(1) and two equivalent Fe(4) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(3), one Fe(5), and one Fe(6) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(4) atoms. There are six inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(4) atom. In the second F site, F(2) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Fe(3), one Fe(5), and one Fe(6) atom. In the fourth F site, F(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(4) atom. In the fifth F site, F(5) is bonded in a distorted T-shaped geometry to one Fe(5) and two equivalent Fe(3) atoms. In the sixth F site, F(6) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(3), and one Fe(6) atom.