MgFe2(OF)2 crystallizes in the monoclinic P2/m space group. Mg(1) is bonded to four equivalent O(1) and two equivalent F(1) atoms to form MgO4F2 octahedra that share edges with two equivalent Mg(1)O4F2 octahedra and edges with four equivalent Fe(1)O2F4 octahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1) and four equivalent F(1) atoms to form FeO2F4 octahedra that share edges with two equivalent Fe(1)O2F4 octahedra and edges with four equivalent Mg(1)O4F2 octahedra. In the second Fe site, Fe(2) is bonded in a square co-planar geometry to four equivalent O(1) atoms. O(1) is bonded to two equivalent Mg(1), one Fe(1), and two equivalent Fe(2) atoms to form a mixture of corner and edge-sharing OMg2Fe3 trigonal bipyramids. F(1) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Fe(1) atoms.
MgFe2(OF)2 crystallizes in the monoclinic P2/m space group. Mg(1) is bonded to four equivalent O(1) and two equivalent F(1) atoms to form MgO4F2 octahedra that share edges with two equivalent Mg(1)O4F2 octahedra and edges with four equivalent Fe(1)O2F4 octahedra. All Mg(1)-O(1) bond lengths are 2.14 Å. Both Mg(1)-F(1) bond lengths are 1.99 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1) and four equivalent F(1) atoms to form FeO2F4 octahedra that share edges with two equivalent Fe(1)O2F4 octahedra and edges with four equivalent Mg(1)O4F2 octahedra. Both Fe(1)-O(1) bond lengths are 2.11 Å. All Fe(1)-F(1) bond lengths are 2.13 Å. In the second Fe site, Fe(2) is bonded in a square co-planar geometry to four equivalent O(1) atoms. All Fe(2)-O(1) bond lengths are 2.09 Å. O(1) is bonded to two equivalent Mg(1), one Fe(1), and two equivalent Fe(2) atoms to form a mixture of corner and edge-sharing OMg2Fe3 trigonal bipyramids. F(1) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Fe(1) atoms.