MgFe4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(4), one F(1), one F(2), and one F(4) atom to form MgO3F3 octahedra that share corners with four equivalent Fe(3)O3F2 trigonal bipyramids and edges with two equivalent Fe(2)O3F3 octahedra. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one F(1), one F(3), and one F(4) atom. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), one O(3), one F(2), one F(3), and one F(4) atom to form distorted FeO3F3 octahedra that share corners with three equivalent Fe(3)O3F2 trigonal bipyramids and edges with two equivalent Mg(1)O3F3 octahedra. In the third Fe site, Fe(3) is bonded to one O(1), one O(3), one O(4), one F(1), and one F(2) atom to form distorted FeO3F2 trigonal bipyramids that share corners with three equivalent Fe(2)O3F3 octahedra and corners with four equivalent Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 30-66°. In the fourth Fe site, Fe(4) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(4), one F(1), one F(2), and one F(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(3) atom. In the second O site, O(2) is bonded in a trigonal pyramidal geometry to one Mg(1), one Fe(1), one Fe(2), and one Fe(4) atom. In the third O site, O(3) is bonded in a see-saw-like geometry to one Mg(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Mg(1), one Fe(1), one Fe(3), and one Fe(4) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(1), one Fe(3), and one Fe(4) atom. In the second F site, F(2) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the third F site, F(3) is bonded in an L-shaped geometry to one Fe(1) and one Fe(2) atom. In the fourth F site, F(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one Fe(4) atom.
MgFe4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(4), one F(1), one F(2), and one F(4) atom to form MgO3F3 octahedra that share corners with four equivalent Fe(3)O3F2 trigonal bipyramids and edges with two equivalent Fe(2)O3F3 octahedra. The Mg(1)-O(2) bond length is 2.09 Å. The Mg(1)-O(3) bond length is 2.11 Å. The Mg(1)-O(4) bond length is 2.16 Å. The Mg(1)-F(1) bond length is 2.00 Å. The Mg(1)-F(2) bond length is 2.07 Å. The Mg(1)-F(4) bond length is 1.96 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one F(1), one F(3), and one F(4) atom. The Fe(1)-O(1) bond length is 1.91 Å. The Fe(1)-O(2) bond length is 1.96 Å. The Fe(1)-O(4) bond length is 1.92 Å. The Fe(1)-F(1) bond length is 2.33 Å. The Fe(1)-F(3) bond length is 2.04 Å. The Fe(1)-F(4) bond length is 2.24 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(2), one O(3), one F(2), one F(3), and one F(4) atom to form distorted FeO3F3 octahedra that share corners with three equivalent Fe(3)O3F2 trigonal bipyramids and edges with two equivalent Mg(1)O3F3 octahedra. The Fe(2)-O(1) bond length is 1.93 Å. The Fe(2)-O(2) bond length is 1.97 Å. The Fe(2)-O(3) bond length is 1.97 Å. The Fe(2)-F(2) bond length is 2.08 Å. The Fe(2)-F(3) bond length is 1.99 Å. The Fe(2)-F(4) bond length is 2.40 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(3), one O(4), one F(1), and one F(2) atom to form distorted FeO3F2 trigonal bipyramids that share corners with three equivalent Fe(2)O3F3 octahedra and corners with four equivalent Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 30-66°. The Fe(3)-O(1) bond length is 2.12 Å. The Fe(3)-O(3) bond length is 2.03 Å. The Fe(3)-O(4) bond length is 2.04 Å. The Fe(3)-F(1) bond length is 2.54 Å. The Fe(3)-F(2) bond length is 2.26 Å. In the fourth Fe site, Fe(4) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(4), one F(1), one F(2), and one F(4) atom. The Fe(4)-O(2) bond length is 1.99 Å. The Fe(4)-O(3) bond length is 2.09 Å. The Fe(4)-O(4) bond length is 2.15 Å. The Fe(4)-F(1) bond length is 2.07 Å. The Fe(4)-F(2) bond length is 2.60 Å. The Fe(4)-F(4) bond length is 2.28 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(3) atom. In the second O site, O(2) is bonded in a trigonal pyramidal geometry to one Mg(1), one Fe(1), one Fe(2), and one Fe(4) atom. In the third O site, O(3) is bonded in a see-saw-like geometry to one Mg(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Mg(1), one Fe(1), one Fe(3), and one Fe(4) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(1), one Fe(3), and one Fe(4) atom. In the second F site, F(2) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the third F site, F(3) is bonded in an L-shaped geometry to one Fe(1) and one Fe(2) atom. In the fourth F site, F(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one Fe(4) atom.