The structure described by MgFe4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to two equivalent O(3), two equivalent O(4), one F(1), and one F(4) atom to form distorted MgO4F2 octahedra that share corners with two equivalent Fe(3)O4F2 octahedra, corners with two equivalent Fe(4)O3F2 trigonal bipyramids, edges with two equivalent Mg(1)O4F2 octahedra, edges with four equivalent Fe(2)O2F4 octahedra,  an edgeedge with one Fe(4)O3F2 trigonal bipyramid, and  a faceface with one Fe(3)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 37-38°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), two equivalent O(1), one F(2), and two equivalent F(3) atoms to form FeO3F3 octahedra that share corners with four equivalent Fe(3)O4F2 octahedra, corners with four equivalent Fe(4)O3F2 trigonal bipyramids, and edges with two equivalent Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-51°. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), two equivalent F(1), and two equivalent F(4) atoms to form FeO2F4 octahedra that share corners with four equivalent Fe(3)O4F2 octahedra, corners with two equivalent Fe(4)O3F2 trigonal bipyramids, edges with two equivalent Fe(2)O2F4 octahedra, and edges with four equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 43-56°. In the third Fe site, Fe(3) is bonded to two equivalent O(2), two equivalent O(4), one F(1), and one F(3) atom to form distorted FeO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(1)O3F3 octahedra, edges with two equivalent Fe(3)O4F2 octahedra, and  a faceface with one Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 37-56°. In the fourth Fe site, Fe(4) is bonded to one O(1), two equivalent O(3), and two equivalent F(2) atoms to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(1)O3F3 octahedra,  an edgeedge with one Mg(1)O4F2 octahedra, and edges with two equivalent Fe(4)O3F2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 27-66°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(4) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(3) atoms. In the third O site, O(3) is bonded to two equivalent Mg(1), one Fe(2), and two equivalent Fe(4) atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Fe(2), and two equivalent Fe(3) atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. There are four inequivalent F sites. In the first F site, F(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(3), and two equivalent Fe(2) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(4) atoms. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Fe(3) and two equivalent Fe(1) atoms. In the fourth F site, F(4) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Fe(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe4(OF)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.237
_cell_length_b   9.824
_cell_length_c   3.021
_cell_angle_alpha   90.066
_cell_angle_beta   90.089
_cell_angle_gamma   98.283
_symmetry_Int_Tables_number   1
_cell_volume   153.799
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Mg  Mg0  1  0.519  0.510  0.471  1.0
  Fe  Fe1  1  0.016  0.997  0.994  1.0
  Fe  Fe2  1  0.021  0.488  0.974  1.0
  Fe  Fe3  1  0.520  0.223  0.496  1.0
  Fe  Fe4  1  0.399  0.782  0.483  1.0
  O  O5  1  0.121  0.899  0.494  1.0
  O  O6  1  0.333  0.135  0.995  1.0
  O  O7  1  0.369  0.618  0.973  1.0
  O  O8  1  0.655  0.369  0.979  1.0
  F  F9  1  0.197  0.374  0.476  1.0
  F  F10  1  0.653  0.883  0.989  1.0
  F  F11  1  0.832  0.115  0.495  1.0
  F  F12  1  0.867  0.606  0.474  1.0
[/CIF]
.
The structure described by MgFe4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to two equivalent O(3), two equivalent O(4), one F(1), and one F(4) atom to form distorted MgO4F2 octahedra that share corners with two equivalent Fe(3)O4F2 octahedra, corners with two equivalent Fe(4)O3F2 trigonal bipyramids, edges with two equivalent Mg(1)O4F2 octahedra, edges with four equivalent Fe(2)O2F4 octahedra,  an edgeedge with one Fe(4)O3F2 trigonal bipyramid, and  a faceface with one Fe(3)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 37-38°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), two equivalent O(1), one F(2), and two equivalent F(3) atoms to form FeO3F3 octahedra that share corners with four equivalent Fe(3)O4F2 octahedra, corners with four equivalent Fe(4)O3F2 trigonal bipyramids, and edges with two equivalent Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-51°. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), two equivalent F(1), and two equivalent F(4) atoms to form FeO2F4 octahedra that share corners with four equivalent Fe(3)O4F2 octahedra, corners with two equivalent Fe(4)O3F2 trigonal bipyramids, edges with two equivalent Fe(2)O2F4 octahedra, and edges with four equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 43-56°. In the third Fe site, Fe(3) is bonded to two equivalent O(2), two equivalent O(4), one F(1), and one F(3) atom to form distorted FeO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(1)O3F3 octahedra, edges with two equivalent Fe(3)O4F2 octahedra, and  a faceface with one Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 37-56°. In the fourth Fe site, Fe(4) is bonded to one O(1), two equivalent O(3), and two equivalent F(2) atoms to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(1)O3F3 octahedra,  an edgeedge with one Mg(1)O4F2 octahedra, and edges with two equivalent Fe(4)O3F2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 27-66°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(4) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(3) atoms. In the third O site, O(3) is bonded to two equivalent Mg(1), one Fe(2), and two equivalent Fe(4) atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Fe(2), and two equivalent Fe(3) atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. There are four inequivalent F sites. In the first F site, F(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(3), and two equivalent Fe(2) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(4) atoms. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Fe(3) and two equivalent Fe(1) atoms. In the fourth F site, F(4) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Fe(2) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe4(OF)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.237
_cell_length_b   9.824
_cell_length_c   3.021
_cell_angle_alpha   90.066
_cell_angle_beta   90.089
_cell_angle_gamma   98.283
_symmetry_Int_Tables_number   1
_cell_volume   153.799
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Mg  Mg0  1  0.519  0.510  0.471  1.0
  Fe  Fe1  1  0.016  0.997  0.994  1.0
  Fe  Fe2  1  0.021  0.488  0.974  1.0
  Fe  Fe3  1  0.520  0.223  0.496  1.0
  Fe  Fe4  1  0.399  0.782  0.483  1.0
  O  O5  1  0.121  0.899  0.494  1.0
  O  O6  1  0.333  0.135  0.995  1.0
  O  O7  1  0.369  0.618  0.973  1.0
  O  O8  1  0.655  0.369  0.979  1.0
  F  F9  1  0.197  0.374  0.476  1.0
  F  F10  1  0.653  0.883  0.989  1.0
  F  F11  1  0.832  0.115  0.495  1.0
  F  F12  1  0.867  0.606  0.474  1.0
[/CIF]
.