The crystal structure described by MgFe8(O7F)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(12), one O(3), one O(5), one O(9), and one F(2) atom to form distorted MgO5F octahedra that share corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(1)O4 trigonal pyramids, edges with two equivalent Fe(7)O5F octahedra, edges with two equivalent Fe(5)O6 octahedra, and  an edgeedge with one Fe(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 44-56°. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form distorted FeO4 trigonal pyramids that share  a cornercorner with one Fe(4)O5F octahedra,  a cornercorner with one Fe(7)O5F octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Mg(1)O5F octahedra,  an edgeedge with one Mg(1)O5F octahedra,  an edgeedge with one Fe(7)O5F octahedra, and  an edgeedge with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-77°. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(12), one O(13), one O(4), and one O(6) atom to form FeO6 octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with four equivalent Fe(8)O5F octahedra, corners with four equivalent Fe(5)O6 octahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid, and  an edgeedge with one Fe(3)O5F octahedra. The corner-sharing octahedral tilt angles range from 43-56°. In the third Fe site, Fe(3) is bonded to one O(13), one O(14), one O(2), one O(4), one O(7), and one F(1) atom to form FeO5F octahedra that share corners with four equivalent Fe(6)O5F octahedra, corners with four equivalent Fe(8)O5F octahedra,  an edgeedge with one Fe(4)O5F octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. In the fourth Fe site, Fe(4) is bonded to one O(11), one O(14), one O(2), one O(3), one O(8), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with four equivalent Fe(6)O5F octahedra, corners with four equivalent Fe(7)O5F octahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid, and  an edgeedge with one Fe(3)O5F octahedra. The corner-sharing octahedral tilt angles range from 44-58°. In the fifth Fe site, Fe(5) is bonded to one O(1), one O(10), one O(12), one O(5), one O(6), and one O(9) atom to form distorted FeO6 octahedra that share corners with four equivalent Fe(2)O6 octahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid,  an edgeedge with one Fe(7)O5F octahedra,  an edgeedge with one Fe(8)O5F octahedra, edges with two equivalent Mg(1)O5F octahedra, and  an edgeedge with one Fe(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 43-53°. In the sixth Fe site, Fe(6) is bonded to one O(11), one O(14), one O(2), one O(7), one O(8), and one F(1) atom to form a mixture of corner and edge-sharing FeO5F octahedra. The corner-sharing octahedral tilt angles range from 46-51°. In the seventh Fe site, Fe(7) is bonded to one O(11), one O(3), one O(5), one O(8), one O(9), and one F(2) atom to form FeO5F octahedra that share corners with four equivalent Fe(4)O5F octahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid,  an edgeedge with one Fe(6)O5F octahedra,  an edgeedge with one Fe(5)O6 octahedra, edges with two equivalent Mg(1)O5F octahedra, and  an edgeedge with one Fe(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 45-58°. In the eighth Fe site, Fe(8) is bonded to one O(10), one O(13), one O(4), one O(6), one O(7), and one F(1) atom to form FeO5F octahedra that share corners with four equivalent Fe(3)O5F octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(6)O5F octahedra, and  an edgeedge with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one Fe(5) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(4), and one Fe(6) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(4), and one Fe(7) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(8) atom. In the fifth O site, O(5) is bonded in a tetrahedral geometry to one Mg(1), one Fe(1), one Fe(5), and one Fe(7) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(5), and one Fe(8) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Fe(3), one Fe(6), and one Fe(8) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Fe(4), one Fe(6), and one Fe(7) atom. In the ninth O site, O(9) is bonded in a distorted see-saw-like geometry to one Mg(1), one Fe(1), one Fe(5), and one Fe(7) atom. In the tenth O site, O(10) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(5), and one Fe(8) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Fe(4), one Fe(6), and one Fe(7) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(5) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(8) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(4), and one Fe(6) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to one Fe(3), one Fe(6), and one Fe(8) atom. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(4), and one Fe(7) atom. is represented by the CIF file [CIF]
data_MgFe8(O7F)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.851
_cell_length_b   4.793
_cell_length_c   11.866
_cell_angle_alpha   90.200
_cell_angle_beta   91.207
_cell_angle_gamma   90.140
_symmetry_Int_Tables_number   1
_cell_volume   275.841
_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  0.952  0.466  0.011  1.0
  Fe  Fe1  1  0.349  0.946  0.008  1.0
  Fe  Fe2  1  0.956  0.989  0.250  1.0
  Fe  Fe3  1  0.996  0.014  0.499  1.0
  Fe  Fe4  1  0.984  0.985  0.745  1.0
  Fe  Fe5  1  0.476  0.474  0.143  1.0
  Fe  Fe6  1  0.477  0.487  0.624  1.0
  Fe  Fe7  1  0.470  0.515  0.856  1.0
  Fe  Fe8  1  0.453  0.483  0.376  1.0
  O  O9  1  0.159  0.755  0.124  1.0
  O  O10  1  0.167  0.805  0.620  1.0
  O  O11  1  0.165  0.792  0.876  1.0
  O  O12  1  0.154  0.801  0.380  1.0
  O  O13  1  0.315  0.323  0.992  1.0
  O  O14  1  0.268  0.276  0.252  1.0
  O  O15  1  0.292  0.305  0.503  1.0
  O  O16  1  0.296  0.295  0.745  1.0
  O  O17  1  0.644  0.706  0.990  1.0
  O  O18  1  0.655  0.687  0.256  1.0
  O  O19  1  0.667  0.696  0.745  1.0
  O  O20  1  0.764  0.206  0.126  1.0
  O  O21  1  0.783  0.182  0.381  1.0
  O  O22  1  0.799  0.185  0.622  1.0
  F  F23  1  0.664  0.686  0.503  1.0
  F  F24  1  0.805  0.235  0.874  1.0
[/CIF]
.
The crystal structure described by MgFe8(O7F)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(12), one O(3), one O(5), one O(9), and one F(2) atom to form distorted MgO5F octahedra that share corners with two equivalent Fe(4)O5F octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(1)O4 trigonal pyramids, edges with two equivalent Fe(7)O5F octahedra, edges with two equivalent Fe(5)O6 octahedra, and  an edgeedge with one Fe(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 44-56°. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form distorted FeO4 trigonal pyramids that share  a cornercorner with one Fe(4)O5F octahedra,  a cornercorner with one Fe(7)O5F octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Fe(5)O6 octahedra, corners with two equivalent Mg(1)O5F octahedra,  an edgeedge with one Mg(1)O5F octahedra,  an edgeedge with one Fe(7)O5F octahedra, and  an edgeedge with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-77°. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(12), one O(13), one O(4), and one O(6) atom to form FeO6 octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with four equivalent Fe(8)O5F octahedra, corners with four equivalent Fe(5)O6 octahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid, and  an edgeedge with one Fe(3)O5F octahedra. The corner-sharing octahedral tilt angles range from 43-56°. In the third Fe site, Fe(3) is bonded to one O(13), one O(14), one O(2), one O(4), one O(7), and one F(1) atom to form FeO5F octahedra that share corners with four equivalent Fe(6)O5F octahedra, corners with four equivalent Fe(8)O5F octahedra,  an edgeedge with one Fe(4)O5F octahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. In the fourth Fe site, Fe(4) is bonded to one O(11), one O(14), one O(2), one O(3), one O(8), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with four equivalent Fe(6)O5F octahedra, corners with four equivalent Fe(7)O5F octahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid, and  an edgeedge with one Fe(3)O5F octahedra. The corner-sharing octahedral tilt angles range from 44-58°. In the fifth Fe site, Fe(5) is bonded to one O(1), one O(10), one O(12), one O(5), one O(6), and one O(9) atom to form distorted FeO6 octahedra that share corners with four equivalent Fe(2)O6 octahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid,  an edgeedge with one Fe(7)O5F octahedra,  an edgeedge with one Fe(8)O5F octahedra, edges with two equivalent Mg(1)O5F octahedra, and  an edgeedge with one Fe(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 43-53°. In the sixth Fe site, Fe(6) is bonded to one O(11), one O(14), one O(2), one O(7), one O(8), and one F(1) atom to form a mixture of corner and edge-sharing FeO5F octahedra. The corner-sharing octahedral tilt angles range from 46-51°. In the seventh Fe site, Fe(7) is bonded to one O(11), one O(3), one O(5), one O(8), one O(9), and one F(2) atom to form FeO5F octahedra that share corners with four equivalent Fe(4)O5F octahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid,  an edgeedge with one Fe(6)O5F octahedra,  an edgeedge with one Fe(5)O6 octahedra, edges with two equivalent Mg(1)O5F octahedra, and  an edgeedge with one Fe(1)O4 trigonal pyramid. The corner-sharing octahedral tilt angles range from 45-58°. In the eighth Fe site, Fe(8) is bonded to one O(10), one O(13), one O(4), one O(6), one O(7), and one F(1) atom to form FeO5F octahedra that share corners with four equivalent Fe(3)O5F octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(6)O5F octahedra, and  an edgeedge with one Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-53°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one Fe(5) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(4), and one Fe(6) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(4), and one Fe(7) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(8) atom. In the fifth O site, O(5) is bonded in a tetrahedral geometry to one Mg(1), one Fe(1), one Fe(5), and one Fe(7) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(5), and one Fe(8) atom. In the seventh O site, O(7) is bonded in a trigonal planar geometry to one Fe(3), one Fe(6), and one Fe(8) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Fe(4), one Fe(6), and one Fe(7) atom. In the ninth O site, O(9) is bonded in a distorted see-saw-like geometry to one Mg(1), one Fe(1), one Fe(5), and one Fe(7) atom. In the tenth O site, O(10) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(5), and one Fe(8) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Fe(4), one Fe(6), and one Fe(7) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(5) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(8) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(4), and one Fe(6) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to one Fe(3), one Fe(6), and one Fe(8) atom. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(4), and one Fe(7) atom. is represented by the CIF file [CIF]
data_MgFe8(O7F)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.851
_cell_length_b   4.793
_cell_length_c   11.866
_cell_angle_alpha   90.200
_cell_angle_beta   91.207
_cell_angle_gamma   90.140
_symmetry_Int_Tables_number   1
_cell_volume   275.841
_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  0.952  0.466  0.011  1.0
  Fe  Fe1  1  0.349  0.946  0.008  1.0
  Fe  Fe2  1  0.956  0.989  0.250  1.0
  Fe  Fe3  1  0.996  0.014  0.499  1.0
  Fe  Fe4  1  0.984  0.985  0.745  1.0
  Fe  Fe5  1  0.476  0.474  0.143  1.0
  Fe  Fe6  1  0.477  0.487  0.624  1.0
  Fe  Fe7  1  0.470  0.515  0.856  1.0
  Fe  Fe8  1  0.453  0.483  0.376  1.0
  O  O9  1  0.159  0.755  0.124  1.0
  O  O10  1  0.167  0.805  0.620  1.0
  O  O11  1  0.165  0.792  0.876  1.0
  O  O12  1  0.154  0.801  0.380  1.0
  O  O13  1  0.315  0.323  0.992  1.0
  O  O14  1  0.268  0.276  0.252  1.0
  O  O15  1  0.292  0.305  0.503  1.0
  O  O16  1  0.296  0.295  0.745  1.0
  O  O17  1  0.644  0.706  0.990  1.0
  O  O18  1  0.655  0.687  0.256  1.0
  O  O19  1  0.667  0.696  0.745  1.0
  O  O20  1  0.764  0.206  0.126  1.0
  O  O21  1  0.783  0.182  0.381  1.0
  O  O22  1  0.799  0.185  0.622  1.0
  F  F23  1  0.664  0.686  0.503  1.0
  F  F24  1  0.805  0.235  0.874  1.0
[/CIF]
.