The crystal structure described by MgFe8(OF)8 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one F(5), one F(7), and one F(8) atom to form distorted MgO3F3 octahedra that share  a cornercorner with one Fe(7)O3F2 trigonal bipyramid, corners with two equivalent Fe(1)O3F2 trigonal bipyramids, corners with two equivalent Fe(3)O3F2 trigonal bipyramids, edges with two equivalent Fe(6)O3F3 octahedra, and  an edgeedge with one Fe(7)O3F2 trigonal bipyramid. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), one O(6), one O(8), one F(1), and one F(8) atom to form FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(5)O3F2 trigonal bipyramids, corners with two equivalent Fe(7)O3F2 trigonal bipyramids, and  an edgeedge with one Fe(2)O3F2 square pyramid. The corner-sharing octahedral tilt angles range from 23-57°. In the second Fe site, Fe(2) is bonded to one O(1), one O(4), one O(8), one F(1), and one F(6) atom to form a mixture of distorted corner and edge-sharing FeO3F2 square pyramids. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(7), one F(6), and one F(7) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O3F3 octahedra, corners with three equivalent Fe(6)O3F3 octahedra, corners with two equivalent Fe(8)O3F2 trigonal bipyramids, and  an edgeedge with one Fe(2)O3F2 square pyramid. The corner-sharing octahedral tilt angles range from 36-53°. In the fourth Fe site, Fe(4) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(5), and one F(8) atom. In the fifth Fe site, Fe(5) is bonded to one O(4), one O(6), one O(8), one F(2), and one F(4) atom to form a mixture of distorted corner and edge-sharing FeO3F2 trigonal bipyramids. In the sixth Fe site, Fe(6) is bonded to one O(2), one O(5), one O(7), one F(3), one F(5), and one F(7) atom to form FeO3F3 octahedra that share corners with three equivalent Fe(3)O3F2 trigonal bipyramids, edges with two equivalent Mg(1)O3F3 octahedra,  an edgeedge with one Fe(7)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(8)O3F2 trigonal bipyramid. In the seventh Fe site, Fe(7) is bonded to one O(3), one O(5), one O(6), one F(2), and one F(5) atom to form FeO3F2 trigonal bipyramids that share  a cornercorner with one Mg(1)O3F3 octahedra, corners with two equivalent Fe(1)O3F2 trigonal bipyramids,  an edgeedge with one Mg(1)O3F3 octahedra,  an edgeedge with one Fe(6)O3F3 octahedra, and  an edgeedge with one Fe(5)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles are 69°. In the eighth Fe site, Fe(8) is bonded to one O(1), one O(4), one O(7), one F(3), and one F(4) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Fe(2)O3F2 square pyramids, corners with two equivalent Fe(3)O3F2 trigonal bipyramids,  an edgeedge with one Fe(6)O3F3 octahedra, and  an edgeedge with one Fe(5)O3F2 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(8) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(3), one Fe(4), and one Fe(6) atom. In the third O site, O(3) is bonded in a distorted 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 trigonal planar geometry to one Fe(2), one Fe(5), and one Fe(8) atom. In the fifth O site, O(5) is bonded in a trigonal pyramidal geometry to one Mg(1), one Fe(4), one Fe(6), and one Fe(7) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(1), one Fe(5), and one Fe(7) atom. In the seventh O site, O(7) is bonded in a distorted 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 trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(5) atom. There are eight inequivalent F sites. In the first F site, F(1) is bonded in a water-like geometry to one Fe(1) and one Fe(2) atom. In the second F site, F(2) is bonded in an L-shaped geometry to one Fe(5) and one Fe(7) atom. In the third F site, F(3) is bonded in an L-shaped geometry to one Fe(6) and one Fe(8) atom. In the fourth F site, F(4) is bonded in a water-like geometry to one Fe(5) and one Fe(8) atom. In the fifth F site, F(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(6), and one Fe(7) atom. In the sixth F site, F(6) is bonded in a water-like geometry to one Fe(2) and one Fe(3) atom. In the seventh F site, F(7) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(3), and one Fe(6) atom. In the eighth F site, F(8) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one Fe(4) atom. is represented by the CIF card [CIF]
data_MgFe8(OF)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.329
_cell_length_b   5.093
_cell_length_c   11.675
_cell_angle_alpha   90.397
_cell_angle_beta   89.232
_cell_angle_gamma   90.606
_symmetry_Int_Tables_number   1
_cell_volume   316.842
_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  0.970  0.486  0.742  1.0
  Fe  Fe1  1  0.927  0.939  0.997  1.0
  Fe  Fe2  1  0.069  0.068  0.248  1.0
  Fe  Fe3  1  0.939  0.927  0.498  1.0
  Fe  Fe4  1  0.209  0.994  0.746  1.0
  Fe  Fe5  1  0.580  0.427  0.128  1.0
  Fe  Fe6  1  0.475  0.524  0.614  1.0
  Fe  Fe7  1  0.435  0.554  0.888  1.0
  Fe  Fe8  1  0.424  0.572  0.369  1.0
  O  O9  1  0.154  0.817  0.367  1.0
  O  O10  1  0.118  0.758  0.623  1.0
  O  O11  1  0.137  0.757  0.880  1.0
  O  O12  1  0.339  0.320  0.244  1.0
  O  O13  1  0.330  0.347  0.755  1.0
  O  O14  1  0.657  0.685  0.005  1.0
  O  O15  1  0.643  0.718  0.488  1.0
  O  O16  1  0.847  0.182  0.122  1.0
  F  F17  1  0.158  0.812  0.119  1.0
  F  F18  1  0.361  0.273  1.000  1.0
  F  F19  1  0.308  0.307  0.483  1.0
  F  F20  1  0.670  0.691  0.246  1.0
  F  F21  1  0.671  0.707  0.765  1.0
  F  F22  1  0.843  0.193  0.374  1.0
  F  F23  1  0.835  0.235  0.621  1.0
  F  F24  1  0.870  0.209  0.870  1.0
[/CIF]
.
The crystal structure described by MgFe8(OF)8 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one O(3), one O(5), one F(5), one F(7), and one F(8) atom to form distorted MgO3F3 octahedra that share  a cornercorner with one Fe(7)O3F2 trigonal bipyramid, corners with two equivalent Fe(1)O3F2 trigonal bipyramids, corners with two equivalent Fe(3)O3F2 trigonal bipyramids, edges with two equivalent Fe(6)O3F3 octahedra, and  an edgeedge with one Fe(7)O3F2 trigonal bipyramid. There are eight inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), one O(6), one O(8), one F(1), and one F(8) atom to form FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(5)O3F2 trigonal bipyramids, corners with two equivalent Fe(7)O3F2 trigonal bipyramids, and  an edgeedge with one Fe(2)O3F2 square pyramid. The corner-sharing octahedral tilt angles range from 23-57°. In the second Fe site, Fe(2) is bonded to one O(1), one O(4), one O(8), one F(1), and one F(6) atom to form a mixture of distorted corner and edge-sharing FeO3F2 square pyramids. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(7), one F(6), and one F(7) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O3F3 octahedra, corners with three equivalent Fe(6)O3F3 octahedra, corners with two equivalent Fe(8)O3F2 trigonal bipyramids, and  an edgeedge with one Fe(2)O3F2 square pyramid. The corner-sharing octahedral tilt angles range from 36-53°. In the fourth Fe site, Fe(4) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(5), and one F(8) atom. In the fifth Fe site, Fe(5) is bonded to one O(4), one O(6), one O(8), one F(2), and one F(4) atom to form a mixture of distorted corner and edge-sharing FeO3F2 trigonal bipyramids. In the sixth Fe site, Fe(6) is bonded to one O(2), one O(5), one O(7), one F(3), one F(5), and one F(7) atom to form FeO3F3 octahedra that share corners with three equivalent Fe(3)O3F2 trigonal bipyramids, edges with two equivalent Mg(1)O3F3 octahedra,  an edgeedge with one Fe(7)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(8)O3F2 trigonal bipyramid. In the seventh Fe site, Fe(7) is bonded to one O(3), one O(5), one O(6), one F(2), and one F(5) atom to form FeO3F2 trigonal bipyramids that share  a cornercorner with one Mg(1)O3F3 octahedra, corners with two equivalent Fe(1)O3F2 trigonal bipyramids,  an edgeedge with one Mg(1)O3F3 octahedra,  an edgeedge with one Fe(6)O3F3 octahedra, and  an edgeedge with one Fe(5)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles are 69°. In the eighth Fe site, Fe(8) is bonded to one O(1), one O(4), one O(7), one F(3), and one F(4) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Fe(2)O3F2 square pyramids, corners with two equivalent Fe(3)O3F2 trigonal bipyramids,  an edgeedge with one Fe(6)O3F3 octahedra, and  an edgeedge with one Fe(5)O3F2 trigonal bipyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(2), one Fe(3), and one Fe(8) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(3), one Fe(4), and one Fe(6) atom. In the third O site, O(3) is bonded in a distorted 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 trigonal planar geometry to one Fe(2), one Fe(5), and one Fe(8) atom. In the fifth O site, O(5) is bonded in a trigonal pyramidal geometry to one Mg(1), one Fe(4), one Fe(6), and one Fe(7) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(1), one Fe(5), and one Fe(7) atom. In the seventh O site, O(7) is bonded in a distorted 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 trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(5) atom. There are eight inequivalent F sites. In the first F site, F(1) is bonded in a water-like geometry to one Fe(1) and one Fe(2) atom. In the second F site, F(2) is bonded in an L-shaped geometry to one Fe(5) and one Fe(7) atom. In the third F site, F(3) is bonded in an L-shaped geometry to one Fe(6) and one Fe(8) atom. In the fourth F site, F(4) is bonded in a water-like geometry to one Fe(5) and one Fe(8) atom. In the fifth F site, F(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(6), and one Fe(7) atom. In the sixth F site, F(6) is bonded in a water-like geometry to one Fe(2) and one Fe(3) atom. In the seventh F site, F(7) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(3), and one Fe(6) atom. In the eighth F site, F(8) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one Fe(4) atom. is represented by the CIF card [CIF]
data_MgFe8(OF)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.329
_cell_length_b   5.093
_cell_length_c   11.675
_cell_angle_alpha   90.397
_cell_angle_beta   89.232
_cell_angle_gamma   90.606
_symmetry_Int_Tables_number   1
_cell_volume   316.842
_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  0.970  0.486  0.742  1.0
  Fe  Fe1  1  0.927  0.939  0.997  1.0
  Fe  Fe2  1  0.069  0.068  0.248  1.0
  Fe  Fe3  1  0.939  0.927  0.498  1.0
  Fe  Fe4  1  0.209  0.994  0.746  1.0
  Fe  Fe5  1  0.580  0.427  0.128  1.0
  Fe  Fe6  1  0.475  0.524  0.614  1.0
  Fe  Fe7  1  0.435  0.554  0.888  1.0
  Fe  Fe8  1  0.424  0.572  0.369  1.0
  O  O9  1  0.154  0.817  0.367  1.0
  O  O10  1  0.118  0.758  0.623  1.0
  O  O11  1  0.137  0.757  0.880  1.0
  O  O12  1  0.339  0.320  0.244  1.0
  O  O13  1  0.330  0.347  0.755  1.0
  O  O14  1  0.657  0.685  0.005  1.0
  O  O15  1  0.643  0.718  0.488  1.0
  O  O16  1  0.847  0.182  0.122  1.0
  F  F17  1  0.158  0.812  0.119  1.0
  F  F18  1  0.361  0.273  1.000  1.0
  F  F19  1  0.308  0.307  0.483  1.0
  F  F20  1  0.670  0.691  0.246  1.0
  F  F21  1  0.671  0.707  0.765  1.0
  F  F22  1  0.843  0.193  0.374  1.0
  F  F23  1  0.835  0.235  0.621  1.0
  F  F24  1  0.870  0.209  0.870  1.0
[/CIF]
.