MgFe10(O4F)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(13), one O(3), one O(6), one O(7), and one F(3) atom to form MgO5F octahedra that share corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(5)O5F octahedra, edges with two equivalent Fe(9)O4F2 octahedra, and faces with two equivalent Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 39-52°. There are ten inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(11), one O(12), one O(15), one O(4), one O(8), and one F(1) atom to form FeO5F octahedra that share corners with two equivalent Fe(8)O5F octahedra, corners with four equivalent Fe(10)O5F octahedra,  an edgeedge with one Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(5)O5F octahedra. The corner-sharing octahedral tilt angles range from 44-51°. In the second Fe site, Fe(2) is bonded to one O(13), one O(16), one O(5), one O(6), one O(9), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(9)O4F2 octahedra, corners with two equivalent Fe(8)O5F octahedra,  an edgeedge with one Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 39-56°. In the third Fe site, Fe(3) is bonded to one O(1), one O(11), one O(14), one O(9), one F(1), and one F(2) atom to form a mixture of corner and edge-sharing FeO4F2 octahedra. The corner-sharing octahedral tilt angles range from 42-52°. In the fourth Fe site, Fe(4) is bonded to one O(10), one O(13), one O(3), one O(6), one O(7), and one F(3) atom to form distorted FeO5F octahedra that share corners with four equivalent Fe(9)O4F2 octahedra,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(5)O5F octahedra, and faces with two equivalent Mg(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 43-62°. In the fifth Fe site, Fe(5) is bonded to one O(10), one O(12), one O(2), one O(7), one O(8), and one F(4) atom to form FeO5F octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(9)O4F2 octahedra, corners with two equivalent Fe(10)O5F octahedra,  an edgeedge with one Fe(1)O5F octahedra, and  an edgeedge with one Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 40-52°. In the sixth Fe site, Fe(6) is bonded in a 5-coordinate geometry to one O(1), one O(16), one O(5), one O(9), and one F(3) atom. In the seventh Fe site, Fe(7) is bonded in a 5-coordinate geometry to one O(15), one O(2), one O(3), one O(8), and one F(4) atom. In the eighth Fe site, Fe(8) is bonded to one O(1), one O(11), one O(14), one O(16), one O(4), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with four equivalent Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(10)O5F octahedra. The corner-sharing octahedral tilt angles range from 42-52°. In the ninth Fe site, Fe(9) is bonded to one O(13), one O(3), one O(5), one O(7), one F(3), and one F(4) atom to form distorted FeO4F2 octahedra that share corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(5)O5F octahedra, corners with four equivalent Fe(4)O5F octahedra, and edges with two equivalent Mg(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 43-62°. In the tenth Fe site, Fe(10) is bonded to one O(12), one O(14), one O(15), one O(2), one O(4), and one F(1) atom to form distorted FeO5F octahedra that share corners with two equivalent Fe(3)O4F2 octahedra, corners with two equivalent Fe(5)O5F octahedra, corners with four equivalent Fe(1)O5F octahedra, and  an edgeedge with one Fe(8)O5F octahedra. The corner-sharing octahedral tilt angles range from 44-52°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(6), and one Fe(8) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(10), one Fe(5), and one Fe(7) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to one Mg(1), one Fe(4), one Fe(7), and one Fe(9) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(10), and one Fe(8) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(2), one Fe(6), and one Fe(9) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(4) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(4), one Fe(5), and one Fe(9) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(5), and one Fe(7) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(6) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(4), and one Fe(5) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(8) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(10), and one Fe(5) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(2), one Fe(4), and one Fe(9) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Fe(10), one Fe(3), and one Fe(8) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(10), and one Fe(7) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(6), and one Fe(8) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(10), and one Fe(3) atom. In the second F site, F(2) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(8) atom. In the third F site, F(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(4), one Fe(6), and one Fe(9) atom. In the fourth F site, F(4) is bonded in a distorted trigonal planar geometry to one Fe(5), one Fe(7), and one Fe(9) atom.
MgFe10(O4F)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(13), one O(3), one O(6), one O(7), and one F(3) atom to form MgO5F octahedra that share corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(5)O5F octahedra, edges with two equivalent Fe(9)O4F2 octahedra, and faces with two equivalent Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 39-52°. The Mg(1)-O(10) bond length is 2.05 Å. The Mg(1)-O(13) bond length is 2.02 Å. The Mg(1)-O(3) bond length is 1.98 Å. The Mg(1)-O(6) bond length is 2.12 Å. The Mg(1)-O(7) bond length is 2.05 Å. The Mg(1)-F(3) bond length is 1.97 Å. There are ten inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(11), one O(12), one O(15), one O(4), one O(8), and one F(1) atom to form FeO5F octahedra that share corners with two equivalent Fe(8)O5F octahedra, corners with four equivalent Fe(10)O5F octahedra,  an edgeedge with one Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(5)O5F octahedra. The corner-sharing octahedral tilt angles range from 44-51°. The Fe(1)-O(11) bond length is 1.90 Å. The Fe(1)-O(12) bond length is 1.94 Å. The Fe(1)-O(15) bond length is 2.05 Å. The Fe(1)-O(4) bond length is 2.10 Å. The Fe(1)-O(8) bond length is 1.93 Å. The Fe(1)-F(1) bond length is 2.08 Å. In the second Fe site, Fe(2) is bonded to one O(13), one O(16), one O(5), one O(6), one O(9), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(9)O4F2 octahedra, corners with two equivalent Fe(8)O5F octahedra,  an edgeedge with one Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 39-56°. The Fe(2)-O(13) bond length is 2.05 Å. The Fe(2)-O(16) bond length is 2.07 Å. The Fe(2)-O(5) bond length is 2.10 Å. The Fe(2)-O(6) bond length is 2.02 Å. The Fe(2)-O(9) bond length is 1.98 Å. The Fe(2)-F(2) bond length is 2.07 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(11), one O(14), one O(9), one F(1), and one F(2) atom to form a mixture of corner and edge-sharing FeO4F2 octahedra. The corner-sharing octahedral tilt angles range from 42-52°. The Fe(3)-O(1) bond length is 2.04 Å. The Fe(3)-O(11) bond length is 1.96 Å. The Fe(3)-O(14) bond length is 2.05 Å. The Fe(3)-O(9) bond length is 1.94 Å. The Fe(3)-F(1) bond length is 2.02 Å. The Fe(3)-F(2) bond length is 2.09 Å. In the fourth Fe site, Fe(4) is bonded to one O(10), one O(13), one O(3), one O(6), one O(7), and one F(3) atom to form distorted FeO5F octahedra that share corners with four equivalent Fe(9)O4F2 octahedra,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(5)O5F octahedra, and faces with two equivalent Mg(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 43-62°. The Fe(4)-O(10) bond length is 1.83 Å. The Fe(4)-O(13) bond length is 1.89 Å. The Fe(4)-O(3) bond length is 1.99 Å. The Fe(4)-O(6) bond length is 1.84 Å. The Fe(4)-O(7) bond length is 1.98 Å. The Fe(4)-F(3) bond length is 2.36 Å. In the fifth Fe site, Fe(5) is bonded to one O(10), one O(12), one O(2), one O(7), one O(8), and one F(4) atom to form FeO5F octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(9)O4F2 octahedra, corners with two equivalent Fe(10)O5F octahedra,  an edgeedge with one Fe(1)O5F octahedra, and  an edgeedge with one Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 40-52°. The Fe(5)-O(10) bond length is 2.01 Å. The Fe(5)-O(12) bond length is 1.97 Å. The Fe(5)-O(2) bond length is 1.99 Å. The Fe(5)-O(7) bond length is 2.11 Å. The Fe(5)-O(8) bond length is 1.99 Å. The Fe(5)-F(4) bond length is 2.26 Å. In the sixth Fe site, Fe(6) is bonded in a 5-coordinate geometry to one O(1), one O(16), one O(5), one O(9), and one F(3) atom. The Fe(6)-O(1) bond length is 1.91 Å. The Fe(6)-O(16) bond length is 2.01 Å. The Fe(6)-O(5) bond length is 1.96 Å. The Fe(6)-O(9) bond length is 1.92 Å. The Fe(6)-F(3) bond length is 2.18 Å. In the seventh Fe site, Fe(7) is bonded in a 5-coordinate geometry to one O(15), one O(2), one O(3), one O(8), and one F(4) atom. The Fe(7)-O(15) bond length is 1.93 Å. The Fe(7)-O(2) bond length is 1.96 Å. The Fe(7)-O(3) bond length is 2.01 Å. The Fe(7)-O(8) bond length is 1.92 Å. The Fe(7)-F(4) bond length is 2.07 Å. In the eighth Fe site, Fe(8) is bonded to one O(1), one O(11), one O(14), one O(16), one O(4), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with four equivalent Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(10)O5F octahedra. The corner-sharing octahedral tilt angles range from 42-52°. The Fe(8)-O(1) bond length is 1.94 Å. The Fe(8)-O(11) bond length is 2.05 Å. The Fe(8)-O(14) bond length is 1.96 Å. The Fe(8)-O(16) bond length is 1.93 Å. The Fe(8)-O(4) bond length is 1.92 Å. The Fe(8)-F(2) bond length is 2.35 Å. In the ninth Fe site, Fe(9) is bonded to one O(13), one O(3), one O(5), one O(7), one F(3), and one F(4) atom to form distorted FeO4F2 octahedra that share corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent Fe(5)O5F octahedra, corners with four equivalent Fe(4)O5F octahedra, and edges with two equivalent Mg(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 43-62°. The Fe(9)-O(13) bond length is 2.39 Å. The Fe(9)-O(3) bond length is 1.90 Å. The Fe(9)-O(5) bond length is 1.89 Å. The Fe(9)-O(7) bond length is 2.02 Å. The Fe(9)-F(3) bond length is 2.06 Å. The Fe(9)-F(4) bond length is 2.14 Å. In the tenth Fe site, Fe(10) is bonded to one O(12), one O(14), one O(15), one O(2), one O(4), and one F(1) atom to form distorted FeO5F octahedra that share corners with two equivalent Fe(3)O4F2 octahedra, corners with two equivalent Fe(5)O5F octahedra, corners with four equivalent Fe(1)O5F octahedra, and  an edgeedge with one Fe(8)O5F octahedra. The corner-sharing octahedral tilt angles range from 44-52°. The Fe(10)-O(12) bond length is 1.97 Å. The Fe(10)-O(14) bond length is 1.92 Å. The Fe(10)-O(15) bond length is 1.95 Å. The Fe(10)-O(2) bond length is 1.91 Å. The Fe(10)-O(4) bond length is 1.96 Å. The Fe(10)-F(1) bond length is 2.42 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(6), and one Fe(8) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(10), one Fe(5), and one Fe(7) atom. In the third O site, O(3) is bonded in a distorted tetrahedral geometry to one Mg(1), one Fe(4), one Fe(7), and one Fe(9) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(10), and one Fe(8) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(2), one Fe(6), and one Fe(9) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(4) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(4), one Fe(5), and one Fe(9) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(5), and one Fe(7) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(6) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(4), and one Fe(5) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(8) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(10), and one Fe(5) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(2), one Fe(4), and one Fe(9) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Fe(10), one Fe(3), and one Fe(8) atom. In the fifteenth O site, O(15) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(10), and one Fe(7) atom. In the sixteenth O site, O(16) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(6), and one Fe(8) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(10), and one Fe(3) atom. In the second F site, F(2) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(8) atom. In the third F site, F(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(4), one Fe(6), and one Fe(9) atom. In the fourth F site, F(4) is bonded in a distorted trigonal planar geometry to one Fe(5), one Fe(7), and one Fe(9) atom.