MgFe10(O4F)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(14), one O(4), one F(1), and one F(2) atom to form distorted MgO3F2 trigonal bipyramids that share  a cornercorner with one Fe(10)O5F octahedra,  a cornercorner with one Fe(2)O5F octahedra,  a cornercorner with one Fe(6)O5F octahedra, corners with two equivalent Fe(1)O5F octahedra,  a cornercorner with one Fe(8)O4F trigonal bipyramid,  an edgeedge with one Fe(10)O5F octahedra,  an edgeedge with one Fe(8)O4F trigonal bipyramid, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 40-70°. 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(7)O5F octahedra, corners with four equivalent Fe(10)O5F octahedra,  a cornercorner with one Fe(3)O5 trigonal bipyramid, corners with two equivalent Mg(1)O3F2 trigonal bipyramids, corners with two equivalent Fe(8)O4F trigonal bipyramids, and  an edgeedge with one Fe(5)O5F octahedra. The corner-sharing octahedral tilt angles range from 41-55°. 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 Fe(9)O4F2 octahedra, corners with four equivalent Fe(6)O5F octahedra,  a cornercorner with one Mg(1)O3F2 trigonal bipyramid, corners with two equivalent Fe(8)O4F trigonal bipyramids, corners with two equivalent Fe(3)O5 trigonal bipyramids, and  an edgeedge with one Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 44-56°. In the third Fe site, Fe(3) is bonded to one O(1), one O(11), one O(14), one O(16), and one O(9) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(1)O5F octahedra,  a cornercorner with one Fe(10)O5F octahedra,  a cornercorner with one Fe(6)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one Fe(8)O4F trigonal bipyramid,  an edgeedge with one Fe(6)O5F octahedra,  an edgeedge with one Mg(1)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(8)O4F trigonal bipyramid. The corner-sharing octahedral tilt angles range from 44-62°. 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 FeO5F octahedra that share corners with two equivalent Fe(6)O5F octahedra, corners with two equivalent Fe(7)O5F octahedra, corners with four equivalent Fe(9)O4F2 octahedra,  an edgeedge with one Fe(2)O5F octahedra, and  an edgeedge with one Fe(5)O5F octahedra. The corner-sharing octahedral tilt angles range from 43-58°. 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 Fe(9)O4F2 octahedra, corners with two equivalent Fe(10)O5F octahedra, corners with four equivalent Fe(7)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 45-52°. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(16), one O(5), one O(6), one O(9), and one F(3) atom to form FeO5F octahedra that share corners with two equivalent Fe(4)O5F octahedra, corners with four equivalent Fe(2)O5F octahedra,  a cornercorner with one Mg(1)O3F2 trigonal bipyramid,  a cornercorner with one Fe(8)O4F trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Fe(9)O4F2 octahedra, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 44-56°. In the seventh Fe site, Fe(7) is bonded to one O(10), one O(15), one O(2), one O(3), one O(8), and one F(4) atom to form FeO5F octahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with four equivalent Fe(5)O5F octahedra,  an edgeedge with one Fe(9)O4F2 octahedra, and  an edgeedge with one Fe(10)O5F octahedra. The corner-sharing octahedral tilt angles range from 45-54°. In the eighth Fe site, Fe(8) is bonded to one O(11), one O(14), one O(16), one O(4), and one F(2) atom to form distorted FeO4F trigonal bipyramids that share  a cornercorner with one Fe(6)O5F octahedra, corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one Mg(1)O3F2 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Fe(10)O5F octahedra,  an edgeedge with one Mg(1)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-75°. 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 a mixture of edge and corner-sharing FeO4F2 octahedra. The corner-sharing octahedral tilt angles range from 43-58°. 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 FeO5F octahedra that share corners with two equivalent Fe(5)O5F octahedra, corners with four equivalent Fe(1)O5F octahedra,  a cornercorner with one Mg(1)O3F2 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Fe(7)O5F octahedra,  an edgeedge with one Mg(1)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(8)O4F trigonal bipyramid. The corner-sharing octahedral tilt angles range from 41-55°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(3), and one Fe(6) 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 trigonal planar geometry to one Fe(4), one Fe(7), and one Fe(9) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(1), one Fe(10), and one Fe(8) atom to form distorted OMgFe3 trigonal pyramids that share  a cornercorner with one O(14)MgFe3 tetrahedra,  a cornercorner with one O(16)Fe4 trigonal pyramid, and  an edgeedge with one O(14)MgFe3 tetrahedra. 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 distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to 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 3-coordinate geometry to one Fe(2), one Fe(3), and one Fe(6) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one Fe(7) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped 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 distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(9) atom. In the fourteenth O site, O(14) is bonded to one Mg(1), one Fe(10), one Fe(3), and one Fe(8) atom to form distorted OMgFe3 tetrahedra that share  a cornercorner with one O(4)MgFe3 trigonal pyramid, corners with two equivalent O(16)Fe4 trigonal pyramids, and  an edgeedge with one O(4)MgFe3 trigonal pyramid. 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 to one Fe(2), one Fe(3), one Fe(6), and one Fe(8) atom to form distorted corner-sharing OFe4 trigonal pyramids. There are four inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one Fe(10) 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(8) atom. In the third F site, F(3) is bonded in a distorted trigonal planar geometry to 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(1), one O(14), one O(4), one F(1), and one F(2) atom to form distorted MgO3F2 trigonal bipyramids that share  a cornercorner with one Fe(10)O5F octahedra,  a cornercorner with one Fe(2)O5F octahedra,  a cornercorner with one Fe(6)O5F octahedra, corners with two equivalent Fe(1)O5F octahedra,  a cornercorner with one Fe(8)O4F trigonal bipyramid,  an edgeedge with one Fe(10)O5F octahedra,  an edgeedge with one Fe(8)O4F trigonal bipyramid, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 40-70°. The Mg(1)-O(1) bond length is 2.06 Å. The Mg(1)-O(14) bond length is 1.99 Å. The Mg(1)-O(4) bond length is 2.00 Å. The Mg(1)-F(1) bond length is 1.94 Å. The Mg(1)-F(2) bond length is 2.00 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(7)O5F octahedra, corners with four equivalent Fe(10)O5F octahedra,  a cornercorner with one Fe(3)O5 trigonal bipyramid, corners with two equivalent Mg(1)O3F2 trigonal bipyramids, corners with two equivalent Fe(8)O4F trigonal bipyramids, and  an edgeedge with one Fe(5)O5F octahedra. The corner-sharing octahedral tilt angles range from 41-55°. The Fe(1)-O(11) bond length is 2.07 Å. The Fe(1)-O(12) bond length is 1.97 Å. The Fe(1)-O(15) bond length is 2.01 Å. The Fe(1)-O(4) bond length is 2.12 Å. The Fe(1)-O(8) bond length is 1.98 Å. The Fe(1)-F(1) bond length is 2.02 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 Fe(9)O4F2 octahedra, corners with four equivalent Fe(6)O5F octahedra,  a cornercorner with one Mg(1)O3F2 trigonal bipyramid, corners with two equivalent Fe(8)O4F trigonal bipyramids, corners with two equivalent Fe(3)O5 trigonal bipyramids, and  an edgeedge with one Fe(4)O5F octahedra. The corner-sharing octahedral tilt angles range from 44-56°. The Fe(2)-O(13) bond length is 1.94 Å. The Fe(2)-O(16) bond length is 2.20 Å. The Fe(2)-O(5) bond length is 1.96 Å. The Fe(2)-O(6) bond length is 2.02 Å. The Fe(2)-O(9) bond length is 2.02 Å. The Fe(2)-F(2) bond length is 2.26 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(11), one O(14), one O(16), and one O(9) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Fe(1)O5F octahedra,  a cornercorner with one Fe(10)O5F octahedra,  a cornercorner with one Fe(6)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one Fe(8)O4F trigonal bipyramid,  an edgeedge with one Fe(6)O5F octahedra,  an edgeedge with one Mg(1)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(8)O4F trigonal bipyramid. The corner-sharing octahedral tilt angles range from 44-62°. The Fe(3)-O(1) bond length is 1.87 Å. The Fe(3)-O(11) bond length is 1.91 Å. The Fe(3)-O(14) bond length is 2.08 Å. The Fe(3)-O(16) bond length is 1.95 Å. The Fe(3)-O(9) bond length is 1.86 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 FeO5F octahedra that share corners with two equivalent Fe(6)O5F octahedra, corners with two equivalent Fe(7)O5F octahedra, corners with four equivalent Fe(9)O4F2 octahedra,  an edgeedge with one Fe(2)O5F octahedra, and  an edgeedge with one Fe(5)O5F octahedra. The corner-sharing octahedral tilt angles range from 43-58°. The Fe(4)-O(10) bond length is 1.90 Å. The Fe(4)-O(13) bond length is 1.97 Å. The Fe(4)-O(3) bond length is 2.03 Å. The Fe(4)-O(6) bond length is 1.92 Å. The Fe(4)-O(7) bond length is 1.98 Å. The Fe(4)-F(3) bond length is 2.19 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 Fe(9)O4F2 octahedra, corners with two equivalent Fe(10)O5F octahedra, corners with four equivalent Fe(7)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 45-52°. The Fe(5)-O(10) bond length is 1.96 Å. The Fe(5)-O(12) bond length is 1.94 Å. The Fe(5)-O(2) bond length is 1.97 Å. The Fe(5)-O(7) bond length is 1.91 Å. The Fe(5)-O(8) bond length is 1.93 Å. The Fe(5)-F(4) bond length is 2.17 Å. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(16), one O(5), one O(6), one O(9), and one F(3) atom to form FeO5F octahedra that share corners with two equivalent Fe(4)O5F octahedra, corners with four equivalent Fe(2)O5F octahedra,  a cornercorner with one Mg(1)O3F2 trigonal bipyramid,  a cornercorner with one Fe(8)O4F trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Fe(9)O4F2 octahedra, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 44-56°. The Fe(6)-O(1) bond length is 1.98 Å. The Fe(6)-O(16) bond length is 2.15 Å. The Fe(6)-O(5) bond length is 1.95 Å. The Fe(6)-O(6) bond length is 1.96 Å. The Fe(6)-O(9) bond length is 2.16 Å. The Fe(6)-F(3) bond length is 2.13 Å. In the seventh Fe site, Fe(7) is bonded to one O(10), one O(15), one O(2), one O(3), one O(8), and one F(4) atom to form FeO5F octahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(4)O5F octahedra, corners with four equivalent Fe(5)O5F octahedra,  an edgeedge with one Fe(9)O4F2 octahedra, and  an edgeedge with one Fe(10)O5F octahedra. The corner-sharing octahedral tilt angles range from 45-54°. The Fe(7)-O(10) bond length is 2.20 Å. The Fe(7)-O(15) bond length is 1.89 Å. The Fe(7)-O(2) bond length is 1.87 Å. The Fe(7)-O(3) bond length is 1.90 Å. The Fe(7)-O(8) bond length is 2.05 Å. The Fe(7)-F(4) bond length is 2.03 Å. In the eighth Fe site, Fe(8) is bonded to one O(11), one O(14), one O(16), one O(4), and one F(2) atom to form distorted FeO4F trigonal bipyramids that share  a cornercorner with one Fe(6)O5F octahedra, corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one Mg(1)O3F2 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Fe(10)O5F octahedra,  an edgeedge with one Mg(1)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 29-75°. The Fe(8)-O(11) bond length is 1.93 Å. The Fe(8)-O(14) bond length is 1.99 Å. The Fe(8)-O(16) bond length is 2.00 Å. The Fe(8)-O(4) bond length is 1.97 Å. The Fe(8)-F(2) bond length is 2.10 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 a mixture of edge and corner-sharing FeO4F2 octahedra. The corner-sharing octahedral tilt angles range from 43-58°. The Fe(9)-O(13) bond length is 2.04 Å. The Fe(9)-O(3) bond length is 1.93 Å. The Fe(9)-O(5) bond length is 1.92 Å. The Fe(9)-O(7) bond length is 2.12 Å. The Fe(9)-F(3) bond length is 2.04 Å. The Fe(9)-F(4) bond length is 2.08 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 FeO5F octahedra that share corners with two equivalent Fe(5)O5F octahedra, corners with four equivalent Fe(1)O5F octahedra,  a cornercorner with one Mg(1)O3F2 trigonal bipyramid,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Fe(7)O5F octahedra,  an edgeedge with one Mg(1)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(8)O4F trigonal bipyramid. The corner-sharing octahedral tilt angles range from 41-55°. The Fe(10)-O(12) bond length is 1.92 Å. The Fe(10)-O(14) bond length is 2.11 Å. The Fe(10)-O(15) bond length is 2.00 Å. The Fe(10)-O(2) bond length is 1.96 Å. The Fe(10)-O(4) bond length is 2.07 Å. The Fe(10)-F(1) bond length is 2.21 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one Fe(3), and one Fe(6) 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 trigonal planar geometry to one Fe(4), one Fe(7), and one Fe(9) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(1), one Fe(10), and one Fe(8) atom to form distorted OMgFe3 trigonal pyramids that share  a cornercorner with one O(14)MgFe3 tetrahedra,  a cornercorner with one O(16)Fe4 trigonal pyramid, and  an edgeedge with one O(14)MgFe3 tetrahedra. 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 distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to 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 3-coordinate geometry to one Fe(2), one Fe(3), and one Fe(6) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Fe(4), one Fe(5), and one Fe(7) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped 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 distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(9) atom. In the fourteenth O site, O(14) is bonded to one Mg(1), one Fe(10), one Fe(3), and one Fe(8) atom to form distorted OMgFe3 tetrahedra that share  a cornercorner with one O(4)MgFe3 trigonal pyramid, corners with two equivalent O(16)Fe4 trigonal pyramids, and  an edgeedge with one O(4)MgFe3 trigonal pyramid. 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 to one Fe(2), one Fe(3), one Fe(6), and one Fe(8) atom to form distorted corner-sharing OFe4 trigonal pyramids. There are four inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one Fe(10) 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(8) atom. In the third F site, F(3) is bonded in a distorted trigonal planar geometry to 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.