MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(4), one O(5), one F(1), one F(2), and one F(5) atom to form MgO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra,  a cornercorner with one Fe(2)O3F2 trigonal bipyramid, edges with two equivalent Fe(5)O3F3 octahedra, edges with two equivalent Fe(6)O3F3 octahedra, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 48-51°. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(3), one O(5), one F(3), one F(4), and one F(6) atom to form FeO3F3 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(5)O3F3 octahedra, corners with two equivalent Fe(6)O3F3 octahedra, corners with three equivalent Fe(4)O3F2 trigonal bipyramids, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 39-63°. In the second Fe site, Fe(2) is bonded to one O(4), one O(5), one O(6), one F(2), and one F(3) atom to form distorted FeO3F2 trigonal bipyramids that share  a cornercorner with one Mg(1)O3F3 octahedra,  a cornercorner with one Fe(5)O3F3 octahedra, corners with three equivalent Fe(6)O3F3 octahedra, corners with two equivalent Fe(4)O3F2 trigonal bipyramids,  an edgeedge with one Mg(1)O3F3 octahedra, and  an edgeedge with one Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 50-63°. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one F(2), and one F(4) atom. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(6), one F(3), and one F(4) atom to form FeO3F2 trigonal bipyramids that share  a cornercorner with one Fe(5)O3F3 octahedra, corners with three equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O3F2 trigonal bipyramids, and  an edgeedge with one Fe(6)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 42-67°. In the fifth Fe site, Fe(5) is bonded to one O(1), one O(3), one O(4), one F(1), one F(5), and one F(6) atom to form FeO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra,  a cornercorner with one Fe(2)O3F2 trigonal bipyramid,  a cornercorner with one Fe(4)O3F2 trigonal bipyramid,  an edgeedge with one Fe(6)O3F3 octahedra, and edges with two equivalent Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 39-63°. In the sixth Fe site, Fe(6) is bonded to one O(2), one O(5), one O(6), one F(1), one F(2), and one F(5) atom to form distorted FeO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra, corners with three equivalent Fe(2)O3F2 trigonal bipyramids,  an edgeedge with one Fe(5)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and  an edgeedge with one Fe(4)O3F2 trigonal bipyramid. 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(3), one Fe(4), and one Fe(5) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(4), and one Fe(6) atom. In the third O site, O(3) is bonded to one Mg(1), one Fe(1), one Fe(3), and one Fe(5) atom to form distorted OMgFe3 trigonal pyramids that share corners with two equivalent O(5)MgFe3 trigonal pyramids, corners with three equivalent O(4)MgFe3 trigonal pyramids, and  an edgeedge with one F(2)MgFe3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), one Fe(3), and one Fe(5) atom to form OMgFe3 trigonal pyramids that share  a cornercorner with one F(2)MgFe3 trigonal pyramid, corners with three equivalent O(3)MgFe3 trigonal pyramids,  an edgeedge with one O(5)MgFe3 trigonal pyramid, and  an edgeedge with one F(2)MgFe3 trigonal pyramid. In the fifth O site, O(5) is bonded to one Mg(1), one Fe(1), one Fe(2), and one Fe(6) atom to form OMgFe3 trigonal pyramids that share corners with two equivalent O(3)MgFe3 trigonal pyramids, corners with three equivalent F(2)MgFe3 trigonal pyramids, and  an edgeedge with one O(4)MgFe3 trigonal pyramid. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(4), and one Fe(6) atom. There are six inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(5), and one Fe(6) atom. In the second F site, F(2) is bonded to one Mg(1), one Fe(2), one Fe(3), and one Fe(6) atom to form distorted FMgFe3 trigonal pyramids that share  a cornercorner with one O(4)MgFe3 trigonal pyramid, corners with three equivalent O(5)MgFe3 trigonal pyramids,  an edgeedge with one O(3)MgFe3 trigonal pyramid, and  an edgeedge with one O(4)MgFe3 trigonal pyramid. In the third F site, F(3) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(4) atom. In the fourth F site, F(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(4) atom. In the fifth F site, F(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(5), and one Fe(6) atom. In the sixth F site, F(6) is bonded in a bent 150 degrees geometry to one Fe(1) and one Fe(5) atom.
MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(4), one O(5), one F(1), one F(2), and one F(5) atom to form MgO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra,  a cornercorner with one Fe(2)O3F2 trigonal bipyramid, edges with two equivalent Fe(5)O3F3 octahedra, edges with two equivalent Fe(6)O3F3 octahedra, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 48-51°. The Mg(1)-O(3) bond length is 2.10 Å. The Mg(1)-O(4) bond length is 2.06 Å. The Mg(1)-O(5) bond length is 2.18 Å. The Mg(1)-F(1) bond length is 1.97 Å. The Mg(1)-F(2) bond length is 2.09 Å. The Mg(1)-F(5) bond length is 1.98 Å. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(3), one O(5), one F(3), one F(4), and one F(6) atom to form FeO3F3 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(5)O3F3 octahedra, corners with two equivalent Fe(6)O3F3 octahedra, corners with three equivalent Fe(4)O3F2 trigonal bipyramids, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 39-63°. The Fe(1)-O(2) bond length is 1.92 Å. The Fe(1)-O(3) bond length is 2.01 Å. The Fe(1)-O(5) bond length is 2.06 Å. The Fe(1)-F(3) bond length is 2.11 Å. The Fe(1)-F(4) bond length is 2.05 Å. The Fe(1)-F(6) bond length is 2.21 Å. In the second Fe site, Fe(2) is bonded to one O(4), one O(5), one O(6), one F(2), and one F(3) atom to form distorted FeO3F2 trigonal bipyramids that share  a cornercorner with one Mg(1)O3F3 octahedra,  a cornercorner with one Fe(5)O3F3 octahedra, corners with three equivalent Fe(6)O3F3 octahedra, corners with two equivalent Fe(4)O3F2 trigonal bipyramids,  an edgeedge with one Mg(1)O3F3 octahedra, and  an edgeedge with one Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 50-63°. The Fe(2)-O(4) bond length is 1.96 Å. The Fe(2)-O(5) bond length is 1.97 Å. The Fe(2)-O(6) bond length is 1.84 Å. The Fe(2)-F(2) bond length is 2.17 Å. The Fe(2)-F(3) bond length is 2.13 Å. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one F(2), and one F(4) atom. The Fe(3)-O(1) bond length is 1.98 Å. The Fe(3)-O(3) bond length is 2.19 Å. The Fe(3)-O(4) bond length is 2.12 Å. The Fe(3)-F(2) bond length is 2.20 Å. The Fe(3)-F(4) bond length is 2.15 Å. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(6), one F(3), and one F(4) atom to form FeO3F2 trigonal bipyramids that share  a cornercorner with one Fe(5)O3F3 octahedra, corners with three equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O3F2 trigonal bipyramids, and  an edgeedge with one Fe(6)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 42-67°. The Fe(4)-O(1) bond length is 1.90 Å. The Fe(4)-O(2) bond length is 1.91 Å. The Fe(4)-O(6) bond length is 1.92 Å. The Fe(4)-F(3) bond length is 2.11 Å. The Fe(4)-F(4) bond length is 2.07 Å. In the fifth Fe site, Fe(5) is bonded to one O(1), one O(3), one O(4), one F(1), one F(5), and one F(6) atom to form FeO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra,  a cornercorner with one Fe(2)O3F2 trigonal bipyramid,  a cornercorner with one Fe(4)O3F2 trigonal bipyramid,  an edgeedge with one Fe(6)O3F3 octahedra, and edges with two equivalent Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 39-63°. The Fe(5)-O(1) bond length is 1.90 Å. The Fe(5)-O(3) bond length is 2.06 Å. The Fe(5)-O(4) bond length is 2.11 Å. The Fe(5)-F(1) bond length is 2.10 Å. The Fe(5)-F(5) bond length is 2.08 Å. The Fe(5)-F(6) bond length is 1.97 Å. In the sixth Fe site, Fe(6) is bonded to one O(2), one O(5), one O(6), one F(1), one F(2), and one F(5) atom to form distorted FeO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra, corners with three equivalent Fe(2)O3F2 trigonal bipyramids,  an edgeedge with one Fe(5)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and  an edgeedge with one Fe(4)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 43-61°. The Fe(6)-O(2) bond length is 2.04 Å. The Fe(6)-O(5) bond length is 2.03 Å. The Fe(6)-O(6) bond length is 2.04 Å. The Fe(6)-F(1) bond length is 2.13 Å. The Fe(6)-F(2) bond length is 2.43 Å. The Fe(6)-F(5) 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(3), one Fe(4), and one Fe(5) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(4), and one Fe(6) atom. In the third O site, O(3) is bonded to one Mg(1), one Fe(1), one Fe(3), and one Fe(5) atom to form distorted OMgFe3 trigonal pyramids that share corners with two equivalent O(5)MgFe3 trigonal pyramids, corners with three equivalent O(4)MgFe3 trigonal pyramids, and  an edgeedge with one F(2)MgFe3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), one Fe(3), and one Fe(5) atom to form OMgFe3 trigonal pyramids that share  a cornercorner with one F(2)MgFe3 trigonal pyramid, corners with three equivalent O(3)MgFe3 trigonal pyramids,  an edgeedge with one O(5)MgFe3 trigonal pyramid, and  an edgeedge with one F(2)MgFe3 trigonal pyramid. In the fifth O site, O(5) is bonded to one Mg(1), one Fe(1), one Fe(2), and one Fe(6) atom to form OMgFe3 trigonal pyramids that share corners with two equivalent O(3)MgFe3 trigonal pyramids, corners with three equivalent F(2)MgFe3 trigonal pyramids, and  an edgeedge with one O(4)MgFe3 trigonal pyramid. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(4), and one Fe(6) atom. There are six inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(5), and one Fe(6) atom. In the second F site, F(2) is bonded to one Mg(1), one Fe(2), one Fe(3), and one Fe(6) atom to form distorted FMgFe3 trigonal pyramids that share  a cornercorner with one O(4)MgFe3 trigonal pyramid, corners with three equivalent O(5)MgFe3 trigonal pyramids,  an edgeedge with one O(3)MgFe3 trigonal pyramid, and  an edgeedge with one O(4)MgFe3 trigonal pyramid. In the third F site, F(3) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(4) atom. In the fourth F site, F(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(4) atom. In the fifth F site, F(5) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(5), and one Fe(6) atom. In the sixth F site, F(6) is bonded in a bent 150 degrees geometry to one Fe(1) and one Fe(5) atom.