MgFe8(O7F)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(12), one O(13), one O(14), one O(2), one O(4), and one F(2) atom to form distorted MgO5F octahedra that share  a cornercorner with one Fe(1)O5F octahedra,  a cornercorner with one Fe(4)O5F octahedra,  a cornercorner with one Fe(5)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra, corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra,  an edgeedge with one Fe(6)O6 octahedra,  a faceface with one Fe(2)O5F octahedra, and  a faceface with one Fe(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(5), and one F(1) atom to form distorted FeO5F octahedra that share  a cornercorner with one Mg(1)O5F octahedra,  a cornercorner with one Fe(6)O6 octahedra, corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(8)O5F octahedra, and  a faceface with one Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-65°. In the second Fe site, Fe(2) is bonded to one O(10), one O(12), one O(3), one O(4), one O(7), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(1)O5F octahedra,  an edgeedge with one Fe(7)O6 octahedra,  a faceface with one Mg(1)O5F octahedra, and  a faceface with one Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-60°. In the third Fe site, Fe(3) is bonded to one O(1), one O(11), one O(4), one O(5), one O(8), and one F(2) atom to form FeO5F octahedra that share  a cornercorner with one Fe(6)O6 octahedra, corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra, corners with two equivalent Fe(7)O6 octahedra, and  an edgeedge with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-60°. In the fourth Fe site, Fe(4) is bonded to one O(10), one O(14), one O(6), one O(7), one O(9), and one F(1) atom to form FeO5F octahedra that share  a cornercorner with one Mg(1)O5F octahedra, corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra, corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, and  an edgeedge with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 34-65°. In the fifth Fe site, Fe(5) is bonded to one O(12), one O(3), one O(5), one O(6), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Mg(1)O5F octahedra,  a cornercorner with one Fe(6)O6 octahedra, corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra, corners with two equivalent Fe(7)O6 octahedra,  an edgeedge with one Fe(3)O5F octahedra, and  an edgeedge with one Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 46-60°. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(10), one O(13), one O(2), one O(3), and one O(7) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(1)O5F octahedra,  a cornercorner with one Fe(3)O5F octahedra,  a cornercorner with one Fe(5)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra,  an edgeedge with one Mg(1)O5F octahedra,  a faceface with one Fe(1)O5F octahedra, and  a faceface with one Fe(2)O5F octahedra. The corner-sharing octahedral tilt angles range from 45-62°. In the seventh Fe site, Fe(7) is bonded to one O(11), one O(12), one O(13), one O(14), one O(4), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Mg(1)O5F octahedra,  a cornercorner with one Fe(6)O6 octahedra, corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(8)O5F octahedra, and  a faceface with one Mg(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 34-59°. In the eighth Fe site, Fe(8) is bonded to one O(11), one O(13), one O(2), one O(6), one O(8), and one F(1) atom to form FeO5F octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(5)O6 octahedra, corners with two equivalent Fe(6)O6 octahedra,  an edgeedge with one Fe(1)O5F octahedra, and  an edgeedge with one Fe(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-57°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(3), and one Fe(6) atom. In the second O site, O(2) is bonded to one Mg(1), one Fe(1), one Fe(6), and one Fe(8) atom to form distorted OMgFe3 tetrahedra that share  a cornercorner with one O(12)MgFe3 trigonal pyramid,  a cornercorner with one O(4)MgFe3 trigonal pyramid, and corners with two equivalent O(10)Fe4 trigonal pyramids. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Fe(1), one Fe(2), one Fe(5), and one Fe(6) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), one Fe(3), and one Fe(7) atom to form distorted OMgFe3 trigonal pyramids that share  a cornercorner with one O(2)MgFe3 tetrahedra,  a cornercorner with one O(10)Fe4 trigonal pyramid, and  a faceface with one O(12)MgFe3 trigonal pyramid. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(5) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one Fe(8) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(5), and one Fe(8) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one Fe(7) atom. In the tenth O site, O(10) is bonded to one Fe(1), one Fe(2), one Fe(4), and one Fe(6) atom to form distorted corner-sharing OFe4 trigonal pyramids. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Fe(3), one Fe(7), and one Fe(8) atom. In the twelfth O site, O(12) is bonded to one Mg(1), one Fe(2), one Fe(5), and one Fe(7) atom to form distorted OMgFe3 trigonal pyramids that share  a cornercorner with one O(2)MgFe3 tetrahedra,  a cornercorner with one O(10)Fe4 trigonal pyramid, and  a faceface with one O(4)MgFe3 trigonal pyramid. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(6), one Fe(7), and one Fe(8) atom. In the fourteenth O site, O(14) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(4), and one Fe(7) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(4), and one Fe(8) atom. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(3) atom.
MgFe8(O7F)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(12), one O(13), one O(14), one O(2), one O(4), and one F(2) atom to form distorted MgO5F octahedra that share  a cornercorner with one Fe(1)O5F octahedra,  a cornercorner with one Fe(4)O5F octahedra,  a cornercorner with one Fe(5)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra, corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra,  an edgeedge with one Fe(6)O6 octahedra,  a faceface with one Fe(2)O5F octahedra, and  a faceface with one Fe(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-62°. The Mg(1)-O(12) bond length is 2.14 Å. The Mg(1)-O(13) bond length is 2.06 Å. The Mg(1)-O(14) bond length is 1.94 Å. The Mg(1)-O(2) bond length is 2.15 Å. The Mg(1)-O(4) bond length is 2.19 Å. The Mg(1)-F(2) bond length is 1.96 Å. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(2), one O(3), one O(5), and one F(1) atom to form distorted FeO5F octahedra that share  a cornercorner with one Mg(1)O5F octahedra,  a cornercorner with one Fe(6)O6 octahedra, corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(8)O5F octahedra, and  a faceface with one Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 40-65°. The Fe(1)-O(1) bond length is 2.13 Å. The Fe(1)-O(10) bond length is 2.01 Å. The Fe(1)-O(2) bond length is 2.05 Å. The Fe(1)-O(3) bond length is 2.20 Å. The Fe(1)-O(5) bond length is 1.92 Å. The Fe(1)-F(1) bond length is 2.04 Å. In the second Fe site, Fe(2) is bonded to one O(10), one O(12), one O(3), one O(4), one O(7), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(1)O5F octahedra,  an edgeedge with one Fe(7)O6 octahedra,  a faceface with one Mg(1)O5F octahedra, and  a faceface with one Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-60°. The Fe(2)-O(10) bond length is 2.03 Å. The Fe(2)-O(12) bond length is 1.97 Å. The Fe(2)-O(3) bond length is 2.05 Å. The Fe(2)-O(4) bond length is 1.96 Å. The Fe(2)-O(7) bond length is 1.97 Å. The Fe(2)-F(2) bond length is 2.09 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(11), one O(4), one O(5), one O(8), and one F(2) atom to form FeO5F octahedra that share  a cornercorner with one Fe(6)O6 octahedra, corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra, corners with two equivalent Fe(7)O6 octahedra, and  an edgeedge with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 32-60°. The Fe(3)-O(1) bond length is 1.95 Å. The Fe(3)-O(11) bond length is 1.94 Å. The Fe(3)-O(4) bond length is 1.97 Å. The Fe(3)-O(5) bond length is 1.99 Å. The Fe(3)-O(8) bond length is 1.96 Å. The Fe(3)-F(2) bond length is 2.21 Å. In the fourth Fe site, Fe(4) is bonded to one O(10), one O(14), one O(6), one O(7), one O(9), and one F(1) atom to form FeO5F octahedra that share  a cornercorner with one Mg(1)O5F octahedra, corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra, corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(7)O6 octahedra, and  an edgeedge with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 34-65°. The Fe(4)-O(10) bond length is 1.97 Å. The Fe(4)-O(14) bond length is 1.84 Å. The Fe(4)-O(6) bond length is 1.94 Å. The Fe(4)-O(7) bond length is 2.01 Å. The Fe(4)-O(9) bond length is 1.98 Å. The Fe(4)-F(1) bond length is 2.10 Å. In the fifth Fe site, Fe(5) is bonded to one O(12), one O(3), one O(5), one O(6), one O(8), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Mg(1)O5F octahedra,  a cornercorner with one Fe(6)O6 octahedra, corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra, corners with two equivalent Fe(7)O6 octahedra,  an edgeedge with one Fe(3)O5F octahedra, and  an edgeedge with one Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 46-60°. The Fe(5)-O(12) bond length is 2.01 Å. The Fe(5)-O(3) bond length is 2.03 Å. The Fe(5)-O(5) bond length is 2.00 Å. The Fe(5)-O(6) bond length is 2.02 Å. The Fe(5)-O(8) bond length is 2.03 Å. The Fe(5)-O(9) bond length is 1.99 Å. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(10), one O(13), one O(2), one O(3), and one O(7) atom to form distorted FeO6 octahedra that share  a cornercorner with one Fe(1)O5F octahedra,  a cornercorner with one Fe(3)O5F octahedra,  a cornercorner with one Fe(5)O6 octahedra,  a cornercorner with one Fe(7)O6 octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(8)O5F octahedra,  an edgeedge with one Mg(1)O5F octahedra,  a faceface with one Fe(1)O5F octahedra, and  a faceface with one Fe(2)O5F octahedra. The corner-sharing octahedral tilt angles range from 45-62°. The Fe(6)-O(1) bond length is 1.84 Å. The Fe(6)-O(10) bond length is 2.13 Å. The Fe(6)-O(13) bond length is 2.04 Å. The Fe(6)-O(2) bond length is 2.01 Å. The Fe(6)-O(3) bond length is 2.14 Å. The Fe(6)-O(7) bond length is 1.93 Å. In the seventh Fe site, Fe(7) is bonded to one O(11), one O(12), one O(13), one O(14), one O(4), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one Mg(1)O5F octahedra,  a cornercorner with one Fe(6)O6 octahedra, corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(5)O6 octahedra,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(8)O5F octahedra, and  a faceface with one Mg(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 34-59°. The Fe(7)-O(11) bond length is 1.95 Å. The Fe(7)-O(12) bond length is 2.15 Å. The Fe(7)-O(13) bond length is 2.04 Å. The Fe(7)-O(14) bond length is 2.07 Å. The Fe(7)-O(4) bond length is 2.05 Å. The Fe(7)-O(9) bond length is 1.98 Å. In the eighth Fe site, Fe(8) is bonded to one O(11), one O(13), one O(2), one O(6), one O(8), and one F(1) atom to form FeO5F octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(3)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(5)O6 octahedra, corners with two equivalent Fe(6)O6 octahedra,  an edgeedge with one Fe(1)O5F octahedra, and  an edgeedge with one Fe(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-57°. The Fe(8)-O(11) bond length is 1.91 Å. The Fe(8)-O(13) bond length is 2.23 Å. The Fe(8)-O(2) bond length is 2.12 Å. The Fe(8)-O(6) bond length is 2.02 Å. The Fe(8)-O(8) bond length is 2.01 Å. The Fe(8)-F(1) bond length is 2.05 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(3), and one Fe(6) atom. In the second O site, O(2) is bonded to one Mg(1), one Fe(1), one Fe(6), and one Fe(8) atom to form distorted OMgFe3 tetrahedra that share  a cornercorner with one O(12)MgFe3 trigonal pyramid,  a cornercorner with one O(4)MgFe3 trigonal pyramid, and corners with two equivalent O(10)Fe4 trigonal pyramids. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Fe(1), one Fe(2), one Fe(5), and one Fe(6) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), one Fe(3), and one Fe(7) atom to form distorted OMgFe3 trigonal pyramids that share  a cornercorner with one O(2)MgFe3 tetrahedra,  a cornercorner with one O(10)Fe4 trigonal pyramid, and  a faceface with one O(12)MgFe3 trigonal pyramid. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(5) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one Fe(8) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(5), and one Fe(8) atom. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one Fe(7) atom. In the tenth O site, O(10) is bonded to one Fe(1), one Fe(2), one Fe(4), and one Fe(6) atom to form distorted corner-sharing OFe4 trigonal pyramids. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Fe(3), one Fe(7), and one Fe(8) atom. In the twelfth O site, O(12) is bonded to one Mg(1), one Fe(2), one Fe(5), and one Fe(7) atom to form distorted OMgFe3 trigonal pyramids that share  a cornercorner with one O(2)MgFe3 tetrahedra,  a cornercorner with one O(10)Fe4 trigonal pyramid, and  a faceface with one O(4)MgFe3 trigonal pyramid. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(6), one Fe(7), and one Fe(8) atom. In the fourteenth O site, O(14) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(4), and one Fe(7) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(4), and one Fe(8) atom. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(3) atom.