The structure described by MgFe4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), two equivalent O(1), two equivalent O(4), and one F(3) atom to form MgO5F octahedra that share corners with two equivalent Fe(1)O2F3 trigonal bipyramids, corners with two equivalent Fe(2)O3F2 trigonal bipyramids, edges with two equivalent Mg(1)O5F octahedra, edges with two equivalent Fe(3)O3F3 octahedra, edges with two equivalent Fe(4)O3F3 octahedra,  an edgeedge with one Fe(1)O2F3 trigonal bipyramid, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(4), one F(2), and two equivalent F(1) atoms to form distorted FeO2F3 trigonal bipyramids that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(3)O3F3 octahedra, corners with four equivalent Fe(4)O3F3 octahedra,  an edgeedge with one Mg(1)O5F octahedra, and edges with two equivalent Fe(1)O2F3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 34-64°. In the second Fe site, Fe(2) is bonded to one O(3), two equivalent O(1), and two equivalent F(4) atoms to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with four equivalent Fe(3)O3F3 octahedra,  an edgeedge with one Mg(1)O5F octahedra, and edges with two equivalent Fe(2)O3F2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 27-62°. In the third Fe site, Fe(3) is bonded to one O(1), two equivalent O(2), one F(4), and two equivalent F(2) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(1)O2F3 trigonal bipyramids, corners with four equivalent Fe(2)O3F2 trigonal bipyramids, edges with two equivalent Mg(1)O5F octahedra, and edges with two equivalent Fe(3)O3F3 octahedra. In the fourth Fe site, Fe(4) is bonded to one O(4), two equivalent O(3), one F(1), and two equivalent F(3) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(2)O3F2 trigonal bipyramids, corners with four equivalent Fe(1)O2F3 trigonal bipyramids, edges with two equivalent Mg(1)O5F octahedra, and edges with two equivalent Fe(4)O3F3 octahedra. There are four 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 a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1) and two equivalent Fe(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(4) atoms. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Fe(4), and two equivalent Fe(1) 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 distorted T-shaped geometry to one Fe(4) and two equivalent Fe(1) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(3) atoms. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Fe(4) atoms. In the fourth F site, F(4) is bonded in a distorted T-shaped geometry to one Fe(3) and two equivalent Fe(2) atoms. is represented by the CIF file [CIF]
data_MgFe4(OF)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.737
_cell_length_b   10.201
_cell_length_c   3.051
_cell_angle_alpha   91.081
_cell_angle_beta   88.975
_cell_angle_gamma   130.790
_symmetry_Int_Tables_number   1
_cell_volume   158.732
_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  0.998  0.256  0.977  1.0
  Fe  Fe1  1  0.959  0.969  0.000  1.0
  Fe  Fe2  1  0.078  0.563  0.989  1.0
  Fe  Fe3  1  0.488  0.489  0.482  1.0
  Fe  Fe4  1  0.480  0.965  0.487  1.0
  O  O5  1  0.134  0.441  0.486  1.0
  O  O6  1  0.360  0.337  0.978  1.0
  O  O7  1  0.351  0.818  0.984  1.0
  O  O8  1  0.851  0.059  0.475  1.0
  F  F9  1  0.164  0.961  0.514  1.0
  F  F10  1  0.658  0.688  0.997  1.0
  F  F11  1  0.626  0.156  0.993  1.0
  F  F12  1  0.841  0.548  0.492  1.0
[/CIF]
.
The structure described by MgFe4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), two equivalent O(1), two equivalent O(4), and one F(3) atom to form MgO5F octahedra that share corners with two equivalent Fe(1)O2F3 trigonal bipyramids, corners with two equivalent Fe(2)O3F2 trigonal bipyramids, edges with two equivalent Mg(1)O5F octahedra, edges with two equivalent Fe(3)O3F3 octahedra, edges with two equivalent Fe(4)O3F3 octahedra,  an edgeedge with one Fe(1)O2F3 trigonal bipyramid, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(4), one F(2), and two equivalent F(1) atoms to form distorted FeO2F3 trigonal bipyramids that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(3)O3F3 octahedra, corners with four equivalent Fe(4)O3F3 octahedra,  an edgeedge with one Mg(1)O5F octahedra, and edges with two equivalent Fe(1)O2F3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 34-64°. In the second Fe site, Fe(2) is bonded to one O(3), two equivalent O(1), and two equivalent F(4) atoms to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with four equivalent Fe(3)O3F3 octahedra,  an edgeedge with one Mg(1)O5F octahedra, and edges with two equivalent Fe(2)O3F2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 27-62°. In the third Fe site, Fe(3) is bonded to one O(1), two equivalent O(2), one F(4), and two equivalent F(2) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(1)O2F3 trigonal bipyramids, corners with four equivalent Fe(2)O3F2 trigonal bipyramids, edges with two equivalent Mg(1)O5F octahedra, and edges with two equivalent Fe(3)O3F3 octahedra. In the fourth Fe site, Fe(4) is bonded to one O(4), two equivalent O(3), one F(1), and two equivalent F(3) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(2)O3F2 trigonal bipyramids, corners with four equivalent Fe(1)O2F3 trigonal bipyramids, edges with two equivalent Mg(1)O5F octahedra, and edges with two equivalent Fe(4)O3F3 octahedra. There are four 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 a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1) and two equivalent Fe(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(4) atoms. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Fe(4), and two equivalent Fe(1) 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 distorted T-shaped geometry to one Fe(4) and two equivalent Fe(1) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(3) atoms. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Fe(4) atoms. In the fourth F site, F(4) is bonded in a distorted T-shaped geometry to one Fe(3) and two equivalent Fe(2) atoms. is represented by the CIF file [CIF]
data_MgFe4(OF)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.737
_cell_length_b   10.201
_cell_length_c   3.051
_cell_angle_alpha   91.081
_cell_angle_beta   88.975
_cell_angle_gamma   130.790
_symmetry_Int_Tables_number   1
_cell_volume   158.732
_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  0.998  0.256  0.977  1.0
  Fe  Fe1  1  0.959  0.969  0.000  1.0
  Fe  Fe2  1  0.078  0.563  0.989  1.0
  Fe  Fe3  1  0.488  0.489  0.482  1.0
  Fe  Fe4  1  0.480  0.965  0.487  1.0
  O  O5  1  0.134  0.441  0.486  1.0
  O  O6  1  0.360  0.337  0.978  1.0
  O  O7  1  0.351  0.818  0.984  1.0
  O  O8  1  0.851  0.059  0.475  1.0
  F  F9  1  0.164  0.961  0.514  1.0
  F  F10  1  0.658  0.688  0.997  1.0
  F  F11  1  0.626  0.156  0.993  1.0
  F  F12  1  0.841  0.548  0.492  1.0
[/CIF]
.