The material structure described by MgFe8(OF)8 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(4), two equivalent O(1), one F(1), and two equivalent F(4) atoms to form MgO3F3 octahedra that share corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, edges with two equivalent Fe(3)O3F3 octahedra, edges with two equivalent Fe(4)O3F3 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(2), one F(7), and two equivalent F(8) atoms to form a mixture of corner and edge-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the second Fe site, Fe(2) is bonded to one O(4), one O(7), two equivalent O(1), and two equivalent O(8) atoms to form distorted FeO6 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with two equivalent Fe(7)O3F3 octahedra, corners with two equivalent Fe(8)O3F3 octahedra, edges with two equivalent Fe(2)O6 octahedra, and  a faceface with one Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 43-54°. In the third Fe site, Fe(3) is bonded to one O(1), two equivalent O(3), one F(3), and two equivalent F(1) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with two equivalent Fe(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the fourth Fe site, Fe(4) is bonded to one O(2), two equivalent O(4), one F(4), and two equivalent F(2) atoms to form distorted FeO3F3 octahedra that share corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with two equivalent Fe(4)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. In the fifth Fe site, Fe(5) is bonded in a trigonal planar geometry to one O(6) and two equivalent O(5) atoms. In the sixth Fe site, Fe(6) is bonded to one F(2), one F(6), two equivalent F(3), and two equivalent F(5) atoms to form FeF6 octahedra that share corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with two equivalent Fe(7)O3F3 octahedra, corners with two equivalent Fe(8)O3F3 octahedra, and edges with two equivalent Fe(6)F6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. In the seventh Fe site, Fe(7) is bonded to one O(5), two equivalent O(7), one F(8), and two equivalent F(6) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(7)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the eighth Fe site, Fe(8) is bonded to one O(8), two equivalent O(6), one F(5), and two equivalent F(7) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(8)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one Fe(3), and two equivalent Fe(2) atoms to form distorted OMg2Fe3 trigonal bipyramids that share edges with two equivalent O(1)Mg2Fe3 trigonal bipyramids and edges with two equivalent O(4)MgFe3 trigonal pyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(4) and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(3) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), and two equivalent Fe(4) atoms to form distorted OMgFe3 trigonal pyramids that share corners with two equivalent O(4)MgFe3 trigonal pyramids and edges with two equivalent O(1)Mg2Fe3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Fe(7) and two equivalent Fe(5) atoms. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Fe(5) and two equivalent Fe(8) atoms. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(7) atoms. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Fe(8) and two equivalent Fe(2) atoms. There are eight inequivalent F sites. In the first F site, F(1) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Fe(3) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(6) 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(6) atoms. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one Fe(4) atom. In the fifth F site, F(5) is bonded in a distorted trigonal planar geometry to one Fe(8) and two equivalent Fe(6) atoms. In the sixth F site, F(6) is bonded in a distorted T-shaped geometry to one Fe(6) and two equivalent Fe(7) atoms. In the seventh F site, F(7) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(8) atoms. In the eighth F site, F(8) is bonded in a distorted trigonal planar geometry to one Fe(7) and two equivalent Fe(1) atoms. is represented by the CIF file [CIF]
data_MgFe8(OF)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.630
_cell_length_b   9.926
_cell_length_c   3.099
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.246
_symmetry_Int_Tables_number   1
_cell_volume   296.200
_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  0.268  0.501  0.000  1.0
  Fe  Fe1  1  0.009  0.002  0.000  1.0
  Fe  Fe2  1  0.979  0.507  0.000  1.0
  Fe  Fe3  1  0.215  0.237  0.500  1.0
  Fe  Fe4  1  0.213  0.764  0.500  1.0
  Fe  Fe5  1  0.593  0.493  0.000  1.0
  Fe  Fe6  1  0.503  0.006  0.000  1.0
  Fe  Fe7  1  0.767  0.267  0.500  1.0
  Fe  Fe8  1  0.753  0.741  0.500  1.0
  O  O9  1  0.134  0.421  0.500  1.0
  O  O10  1  0.090  0.913  0.500  1.0
  O  O11  1  0.132  0.154  0.000  1.0
  O  O12  1  0.144  0.662  0.000  1.0
  O  O13  1  0.609  0.380  0.500  1.0
  O  O14  1  0.654  0.677  0.000  1.0
  O  O15  1  0.868  0.343  0.000  1.0
  O  O16  1  0.896  0.598  0.500  1.0
  F  F17  1  0.344  0.319  0.000  1.0
  F  F18  1  0.339  0.844  0.000  1.0
  F  F19  1  0.387  0.096  0.500  1.0
  F  F20  1  0.370  0.587  0.500  1.0
  F  F21  1  0.608  0.910  0.500  1.0
  F  F22  1  0.670  0.150  0.000  1.0
  F  F23  1  0.851  0.857  0.000  1.0
  F  F24  1  0.894  0.091  0.500  1.0
[/CIF]
.
The material structure described by MgFe8(OF)8 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(4), two equivalent O(1), one F(1), and two equivalent F(4) atoms to form MgO3F3 octahedra that share corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, edges with two equivalent Fe(3)O3F3 octahedra, edges with two equivalent Fe(4)O3F3 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(2), one F(7), and two equivalent F(8) atoms to form a mixture of corner and edge-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the second Fe site, Fe(2) is bonded to one O(4), one O(7), two equivalent O(1), and two equivalent O(8) atoms to form distorted FeO6 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with two equivalent Fe(7)O3F3 octahedra, corners with two equivalent Fe(8)O3F3 octahedra, edges with two equivalent Fe(2)O6 octahedra, and  a faceface with one Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 43-54°. In the third Fe site, Fe(3) is bonded to one O(1), two equivalent O(3), one F(3), and two equivalent F(1) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with two equivalent Fe(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the fourth Fe site, Fe(4) is bonded to one O(2), two equivalent O(4), one F(4), and two equivalent F(2) atoms to form distorted FeO3F3 octahedra that share corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with two equivalent Fe(4)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. In the fifth Fe site, Fe(5) is bonded in a trigonal planar geometry to one O(6) and two equivalent O(5) atoms. In the sixth Fe site, Fe(6) is bonded to one F(2), one F(6), two equivalent F(3), and two equivalent F(5) atoms to form FeF6 octahedra that share corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with two equivalent Fe(7)O3F3 octahedra, corners with two equivalent Fe(8)O3F3 octahedra, and edges with two equivalent Fe(6)F6 octahedra. The corner-sharing octahedral tilt angles range from 47-48°. In the seventh Fe site, Fe(7) is bonded to one O(5), two equivalent O(7), one F(8), and two equivalent F(6) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(7)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the eighth Fe site, Fe(8) is bonded to one O(8), two equivalent O(6), one F(5), and two equivalent F(7) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(8)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-52°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one Fe(3), and two equivalent Fe(2) atoms to form distorted OMg2Fe3 trigonal bipyramids that share edges with two equivalent O(1)Mg2Fe3 trigonal bipyramids and edges with two equivalent O(4)MgFe3 trigonal pyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(4) and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(3) atoms. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), and two equivalent Fe(4) atoms to form distorted OMgFe3 trigonal pyramids that share corners with two equivalent O(4)MgFe3 trigonal pyramids and edges with two equivalent O(1)Mg2Fe3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Fe(7) and two equivalent Fe(5) atoms. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Fe(5) and two equivalent Fe(8) atoms. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(7) atoms. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Fe(8) and two equivalent Fe(2) atoms. There are eight inequivalent F sites. In the first F site, F(1) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Fe(3) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(6) 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(6) atoms. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one Fe(4) atom. In the fifth F site, F(5) is bonded in a distorted trigonal planar geometry to one Fe(8) and two equivalent Fe(6) atoms. In the sixth F site, F(6) is bonded in a distorted T-shaped geometry to one Fe(6) and two equivalent Fe(7) atoms. In the seventh F site, F(7) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(8) atoms. In the eighth F site, F(8) is bonded in a distorted trigonal planar geometry to one Fe(7) and two equivalent Fe(1) atoms. is represented by the CIF file [CIF]
data_MgFe8(OF)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.630
_cell_length_b   9.926
_cell_length_c   3.099
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.246
_symmetry_Int_Tables_number   1
_cell_volume   296.200
_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  0.268  0.501  0.000  1.0
  Fe  Fe1  1  0.009  0.002  0.000  1.0
  Fe  Fe2  1  0.979  0.507  0.000  1.0
  Fe  Fe3  1  0.215  0.237  0.500  1.0
  Fe  Fe4  1  0.213  0.764  0.500  1.0
  Fe  Fe5  1  0.593  0.493  0.000  1.0
  Fe  Fe6  1  0.503  0.006  0.000  1.0
  Fe  Fe7  1  0.767  0.267  0.500  1.0
  Fe  Fe8  1  0.753  0.741  0.500  1.0
  O  O9  1  0.134  0.421  0.500  1.0
  O  O10  1  0.090  0.913  0.500  1.0
  O  O11  1  0.132  0.154  0.000  1.0
  O  O12  1  0.144  0.662  0.000  1.0
  O  O13  1  0.609  0.380  0.500  1.0
  O  O14  1  0.654  0.677  0.000  1.0
  O  O15  1  0.868  0.343  0.000  1.0
  O  O16  1  0.896  0.598  0.500  1.0
  F  F17  1  0.344  0.319  0.000  1.0
  F  F18  1  0.339  0.844  0.000  1.0
  F  F19  1  0.387  0.096  0.500  1.0
  F  F20  1  0.370  0.587  0.500  1.0
  F  F21  1  0.608  0.910  0.500  1.0
  F  F22  1  0.670  0.150  0.000  1.0
  F  F23  1  0.851  0.857  0.000  1.0
  F  F24  1  0.894  0.091  0.500  1.0
[/CIF]
.