MgMn6(OF)6 crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(3) and four equivalent F(2) atoms to form MgO2F4 octahedra that share corners with two equivalent Mn(2)O2F2 tetrahedra, edges with two equivalent Mg(1)O2F4 octahedra, and edges with four equivalent Mn(4)O4F2 octahedra. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to four equivalent O(1) and two equivalent F(3) atoms to form MnO4F2 octahedra that share corners with eight equivalent Mn(3)O3F3 octahedra and edges with two equivalent Mn(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 44-54°. In the second Mn site, Mn(2) is bonded to one O(2), one O(3), and two equivalent F(1) atoms to form MnO2F2 tetrahedra that share  a cornercorner with one Mg(1)O2F4 octahedra, corners with two equivalent Mn(4)O4F2 octahedra, corners with four equivalent Mn(3)O3F3 octahedra, and corners with two equivalent Mn(2)O2F2 tetrahedra. The corner-sharing octahedral tilt angles range from 49-67°. In the third Mn site, Mn(3) is bonded to one O(1), two equivalent O(2), one F(1), and two equivalent F(3) atoms to form MnO3F3 octahedra that share corners with four equivalent Mn(1)O4F2 octahedra, corners with four equivalent Mn(2)O2F2 tetrahedra, and edges with two equivalent Mn(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-54°. In the fourth Mn site, Mn(4) is bonded to four equivalent O(3) and two equivalent F(2) atoms to form MnO4F2 octahedra that share corners with four equivalent Mn(2)O2F2 tetrahedra, edges with two equivalent Mn(4)O4F2 octahedra, and edges with four equivalent Mg(1)O2F4 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Mn(3) and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mn(2) and two equivalent Mn(3) atoms. In the third O site, O(3) is bonded to one Mg(1), one Mn(2), and two equivalent Mn(4) atoms to form a mixture of corner and edge-sharing OMgMn3 tetrahedra. There are three inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal planar geometry to one Mn(3) and two equivalent Mn(2) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to two equivalent Mg(1) and one Mn(4) atom. In the third F site, F(3) is bonded in a 3-coordinate geometry to one Mn(1) and two equivalent Mn(3) atoms.
MgMn6(OF)6 crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(3) and four equivalent F(2) atoms to form MgO2F4 octahedra that share corners with two equivalent Mn(2)O2F2 tetrahedra, edges with two equivalent Mg(1)O2F4 octahedra, and edges with four equivalent Mn(4)O4F2 octahedra. Both Mg(1)-O(3) bond lengths are 2.09 Å. All Mg(1)-F(2) bond lengths are 2.01 Å. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to four equivalent O(1) and two equivalent F(3) atoms to form MnO4F2 octahedra that share corners with eight equivalent Mn(3)O3F3 octahedra and edges with two equivalent Mn(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 44-54°. There are two shorter (1.97 Å) and two longer (1.98 Å) Mn(1)-O(1) bond lengths. Both Mn(1)-F(3) bond lengths are 2.50 Å. In the second Mn site, Mn(2) is bonded to one O(2), one O(3), and two equivalent F(1) atoms to form MnO2F2 tetrahedra that share  a cornercorner with one Mg(1)O2F4 octahedra, corners with two equivalent Mn(4)O4F2 octahedra, corners with four equivalent Mn(3)O3F3 octahedra, and corners with two equivalent Mn(2)O2F2 tetrahedra. The corner-sharing octahedral tilt angles range from 49-67°. The Mn(2)-O(2) bond length is 1.96 Å. The Mn(2)-O(3) bond length is 2.05 Å. There is one shorter (2.05 Å) and one longer (2.06 Å) Mn(2)-F(1) bond length. In the third Mn site, Mn(3) is bonded to one O(1), two equivalent O(2), one F(1), and two equivalent F(3) atoms to form MnO3F3 octahedra that share corners with four equivalent Mn(1)O4F2 octahedra, corners with four equivalent Mn(2)O2F2 tetrahedra, and edges with two equivalent Mn(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-54°. The Mn(3)-O(1) bond length is 1.96 Å. There is one shorter (1.89 Å) and one longer (2.07 Å) Mn(3)-O(2) bond length. The Mn(3)-F(1) bond length is 2.23 Å. There is one shorter (1.98 Å) and one longer (2.17 Å) Mn(3)-F(3) bond length. In the fourth Mn site, Mn(4) is bonded to four equivalent O(3) and two equivalent F(2) atoms to form MnO4F2 octahedra that share corners with four equivalent Mn(2)O2F2 tetrahedra, edges with two equivalent Mn(4)O4F2 octahedra, and edges with four equivalent Mg(1)O2F4 octahedra. All Mn(4)-O(3) bond lengths are 2.02 Å. Both Mn(4)-F(2) bond lengths are 2.22 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Mn(3) and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mn(2) and two equivalent Mn(3) atoms. In the third O site, O(3) is bonded to one Mg(1), one Mn(2), and two equivalent Mn(4) atoms to form a mixture of corner and edge-sharing OMgMn3 tetrahedra. There are three inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal planar geometry to one Mn(3) and two equivalent Mn(2) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to two equivalent Mg(1) and one Mn(4) atom. In the third F site, F(3) is bonded in a 3-coordinate geometry to one Mn(1) and two equivalent Mn(3) atoms.