MgMn4(OF4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one F(8), two equivalent F(1), and two equivalent F(3) atoms to form MgOF5 octahedra that share  a cornercorner with one Mn(3)OF5 octahedra, edges with two equivalent Mg(1)OF5 octahedra, and edges with two equivalent Mn(2)OF5 octahedra. The corner-sharing octahedral tilt angles are 49°. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 8-coordinate geometry to two equivalent O(2), one F(1), one F(2), two equivalent F(3), and two equivalent F(4) atoms. In the second Mn site, Mn(2) is bonded to one O(1), one F(1), two equivalent F(5), and two equivalent F(8) atoms to form distorted MnOF5 octahedra that share corners with two equivalent Mn(4)O2F3 square pyramids, edges with two equivalent Mg(1)OF5 octahedra, and edges with two equivalent Mn(2)OF5 octahedra. In the third Mn site, Mn(3) is bonded to one O(2), one F(7), two equivalent F(2), and two equivalent F(4) atoms to form MnOF5 octahedra that share  a cornercorner with one Mg(1)OF5 octahedra,  a cornercorner with one Mn(4)O2F3 square pyramid, and edges with two equivalent Mn(3)OF5 octahedra. The corner-sharing octahedral tilt angles are 49°. In the fourth Mn site, Mn(4) is bonded to two equivalent O(1), one F(7), and two equivalent F(6) atoms to form MnO2F3 square pyramids that share  a cornercorner with one Mn(3)OF5 octahedra, corners with two equivalent Mn(2)OF5 octahedra, and edges with two equivalent Mn(4)O2F3 square pyramids. The corner-sharing octahedral tilt angles range from 12-54°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Mn(2) and two equivalent Mn(4) atoms. In the second O site, O(2) is bonded to one Mg(1), one Mn(3), and two equivalent Mn(1) atoms to form corner-sharing OMgMn3 tetrahedra. There are eight inequivalent F sites. In the first F site, F(1) is bonded in a distorted see-saw-like geometry to two equivalent Mg(1), one Mn(1), and one Mn(2) atom. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Mn(1) and two equivalent Mn(3) atoms. In the third F site, F(3) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Mn(1) atoms. In the fourth F site, F(4) is bonded in a distorted square co-planar geometry to two equivalent Mn(1) and two equivalent Mn(3) atoms. In the fifth F site, F(5) is bonded in a water-like geometry to two equivalent Mn(2) atoms. In the sixth F site, F(6) is bonded in a water-like geometry to two equivalent Mn(4) atoms. In the seventh F site, F(7) is bonded in a linear geometry to one Mn(3) and one Mn(4) atom. In the eighth F site, F(8) is bonded in a trigonal non-coplanar geometry to one Mg(1) and two equivalent Mn(2) atoms.
MgMn4(OF4)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one F(8), two equivalent F(1), and two equivalent F(3) atoms to form MgOF5 octahedra that share  a cornercorner with one Mn(3)OF5 octahedra, edges with two equivalent Mg(1)OF5 octahedra, and edges with two equivalent Mn(2)OF5 octahedra. The corner-sharing octahedral tilt angles are 49°. The Mg(1)-O(2) bond length is 2.05 Å. The Mg(1)-F(8) bond length is 1.96 Å. Both Mg(1)-F(1) bond lengths are 2.02 Å. Both Mg(1)-F(3) bond lengths are 2.11 Å. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 8-coordinate geometry to two equivalent O(2), one F(1), one F(2), two equivalent F(3), and two equivalent F(4) atoms. Both Mn(1)-O(2) bond lengths are 2.09 Å. The Mn(1)-F(1) bond length is 2.47 Å. The Mn(1)-F(2) bond length is 2.35 Å. There is one shorter (2.39 Å) and one longer (2.40 Å) Mn(1)-F(3) bond length. Both Mn(1)-F(4) bond lengths are 2.53 Å. In the second Mn site, Mn(2) is bonded to one O(1), one F(1), two equivalent F(5), and two equivalent F(8) atoms to form distorted MnOF5 octahedra that share corners with two equivalent Mn(4)O2F3 square pyramids, edges with two equivalent Mg(1)OF5 octahedra, and edges with two equivalent Mn(2)OF5 octahedra. The Mn(2)-O(1) bond length is 1.98 Å. The Mn(2)-F(1) bond length is 2.40 Å. Both Mn(2)-F(5) bond lengths are 2.03 Å. Both Mn(2)-F(8) bond lengths are 2.17 Å. In the third Mn site, Mn(3) is bonded to one O(2), one F(7), two equivalent F(2), and two equivalent F(4) atoms to form MnOF5 octahedra that share  a cornercorner with one Mg(1)OF5 octahedra,  a cornercorner with one Mn(4)O2F3 square pyramid, and edges with two equivalent Mn(3)OF5 octahedra. The corner-sharing octahedral tilt angles are 49°. The Mn(3)-O(2) bond length is 1.92 Å. The Mn(3)-F(7) bond length is 1.88 Å. There is one shorter (2.03 Å) and one longer (2.04 Å) Mn(3)-F(2) bond length. Both Mn(3)-F(4) bond lengths are 2.15 Å. In the fourth Mn site, Mn(4) is bonded to two equivalent O(1), one F(7), and two equivalent F(6) atoms to form MnO2F3 square pyramids that share  a cornercorner with one Mn(3)OF5 octahedra, corners with two equivalent Mn(2)OF5 octahedra, and edges with two equivalent Mn(4)O2F3 square pyramids. The corner-sharing octahedral tilt angles range from 12-54°. Both Mn(4)-O(1) bond lengths are 1.97 Å. The Mn(4)-F(7) bond length is 2.08 Å. Both Mn(4)-F(6) bond lengths are 2.00 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Mn(2) and two equivalent Mn(4) atoms. In the second O site, O(2) is bonded to one Mg(1), one Mn(3), and two equivalent Mn(1) atoms to form corner-sharing OMgMn3 tetrahedra. There are eight inequivalent F sites. In the first F site, F(1) is bonded in a distorted see-saw-like geometry to two equivalent Mg(1), one Mn(1), and one Mn(2) atom. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Mn(1) and two equivalent Mn(3) atoms. In the third F site, F(3) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Mn(1) atoms. In the fourth F site, F(4) is bonded in a distorted square co-planar geometry to two equivalent Mn(1) and two equivalent Mn(3) atoms. In the fifth F site, F(5) is bonded in a water-like geometry to two equivalent Mn(2) atoms. In the sixth F site, F(6) is bonded in a water-like geometry to two equivalent Mn(4) atoms. In the seventh F site, F(7) is bonded in a linear geometry to one Mn(3) and one Mn(4) atom. In the eighth F site, F(8) is bonded in a trigonal non-coplanar geometry to one Mg(1) and two equivalent Mn(2) atoms.