The compound described by MgFe8(OF)8 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), two equivalent O(3), two equivalent O(7), and one F(8) atom to form MgO5F octahedra that share corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(2)O5 square pyramids, edges with two equivalent Mg(1)O5F octahedra, edges with two equivalent Fe(1)O3F3 octahedra, and  a faceface with one Fe(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. 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 FeO3F3 octahedra that share corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with two equivalent Fe(8)O3F3 octahedra, edges with two equivalent Mg(1)O5F octahedra, and edges with two equivalent Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. In the second Fe site, Fe(2) is bonded to one O(4), two equivalent O(1), and two equivalent O(8) atoms to form distorted FeO5 square pyramids that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with two equivalent Fe(8)O3F3 octahedra, and edges with two equivalent Fe(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-74°. 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 distorted FeO3F3 octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(5)O3F3 octahedra, corners with two equivalent Fe(2)O5 square pyramids, edges with two equivalent Fe(3)O3F3 octahedra, and  a faceface with one Mg(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 45-50°. 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 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(5)O3F3 octahedra, corners with two equivalent Fe(2)O5 square pyramids, and edges with two equivalent Fe(4)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. In the fifth Fe site, Fe(5) is bonded to one O(6), two equivalent O(5), one F(1), and two equivalent F(4) atoms to form a mixture of edge and corner-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-52°. 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(8)O3F3 octahedra, and edges with two equivalent Fe(6)F6 octahedra. The corner-sharing octahedral tilt angles range from 45-48°. In the seventh Fe site, Fe(7) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(7), and two equivalent F(6) atoms. 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(5)O3F3 octahedra, corners with two equivalent Fe(2)O5 square pyramids, and edges with two equivalent Fe(8)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 46-52°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(3), and two equivalent Fe(2) atoms to form distorted corner-sharing OMgFe3 tetrahedra. 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 5-coordinate geometry to two equivalent Mg(1), one Fe(1), and two equivalent Fe(3) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(4) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(7) and two equivalent Fe(5) atoms. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(5) and two equivalent Fe(8) atoms. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Fe(7) atoms. In the eighth O site, O(8) is bonded in a distorted 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 Fe(5) 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 distorted T-shaped geometry to one Fe(4) and two equivalent Fe(5) atoms. In the fifth F site, F(5) is bonded in a distorted T-shaped 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 3-coordinate geometry to one Mg(1) and two equivalent Fe(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe8(OF)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.808
_cell_length_b   9.892
_cell_length_c   3.048
_cell_angle_alpha   89.890
_cell_angle_beta   89.802
_cell_angle_gamma   89.542
_symmetry_Int_Tables_number   1
_cell_volume   295.642
_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  0.990  0.242  0.479  1.0
  Fe  Fe1  1  0.028  0.981  0.982  1.0
  Fe  Fe2  1  0.018  0.525  0.988  1.0
  Fe  Fe3  1  0.254  0.265  0.507  1.0
  Fe  Fe4  1  0.236  0.745  0.485  1.0
  Fe  Fe5  1  0.519  0.517  1.000  1.0
  Fe  Fe6  1  0.497  0.991  0.002  1.0
  Fe  Fe7  1  0.716  0.273  0.496  1.0
  Fe  Fe8  1  0.758  0.725  0.494  1.0
  O  O9  1  0.094  0.410  0.489  1.0
  O  O10  1  0.113  0.898  0.482  1.0
  O  O11  1  0.110  0.161  0.982  1.0
  O  O12  1  0.164  0.655  0.986  1.0
  O  O13  1  0.593  0.417  0.500  1.0
  O  O14  1  0.651  0.658  0.996  1.0
  O  O15  1  0.842  0.301  0.991  1.0
  O  O16  1  0.905  0.596  0.489  1.0
  F  F17  1  0.362  0.371  0.005  1.0
  F  F18  1  0.356  0.840  0.987  1.0
  F  F19  1  0.390  0.100  0.503  1.0
  F  F20  1  0.407  0.610  0.497  1.0
  F  F21  1  0.614  0.901  0.499  1.0
  F  F22  1  0.626  0.158  0.001  1.0
  F  F23  1  0.855  0.839  0.989  1.0
  F  F24  1  0.895  0.064  0.486  1.0
[/CIF]
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The compound described by MgFe8(OF)8 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), two equivalent O(3), two equivalent O(7), and one F(8) atom to form MgO5F octahedra that share corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(2)O5 square pyramids, edges with two equivalent Mg(1)O5F octahedra, edges with two equivalent Fe(1)O3F3 octahedra, and  a faceface with one Fe(3)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. 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 FeO3F3 octahedra that share corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with two equivalent Fe(8)O3F3 octahedra, edges with two equivalent Mg(1)O5F octahedra, and edges with two equivalent Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. In the second Fe site, Fe(2) is bonded to one O(4), two equivalent O(1), and two equivalent O(8) atoms to form distorted FeO5 square pyramids that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(3)O3F3 octahedra, corners with two equivalent Fe(4)O3F3 octahedra, corners with two equivalent Fe(8)O3F3 octahedra, and edges with two equivalent Fe(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-74°. 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 distorted FeO3F3 octahedra that share corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(6)F6 octahedra, corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(5)O3F3 octahedra, corners with two equivalent Fe(2)O5 square pyramids, edges with two equivalent Fe(3)O3F3 octahedra, and  a faceface with one Mg(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 45-50°. 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 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(5)O3F3 octahedra, corners with two equivalent Fe(2)O5 square pyramids, and edges with two equivalent Fe(4)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. In the fifth Fe site, Fe(5) is bonded to one O(6), two equivalent O(5), one F(1), and two equivalent F(4) atoms to form a mixture of edge and corner-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-52°. 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(8)O3F3 octahedra, and edges with two equivalent Fe(6)F6 octahedra. The corner-sharing octahedral tilt angles range from 45-48°. In the seventh Fe site, Fe(7) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(7), and two equivalent F(6) atoms. 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(5)O3F3 octahedra, corners with two equivalent Fe(2)O5 square pyramids, and edges with two equivalent Fe(8)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 46-52°. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(3), and two equivalent Fe(2) atoms to form distorted corner-sharing OMgFe3 tetrahedra. 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 5-coordinate geometry to two equivalent Mg(1), one Fe(1), and two equivalent Fe(3) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(4) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(7) and two equivalent Fe(5) atoms. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(5) and two equivalent Fe(8) atoms. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Fe(7) atoms. In the eighth O site, O(8) is bonded in a distorted 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 Fe(5) 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 distorted T-shaped geometry to one Fe(4) and two equivalent Fe(5) atoms. In the fifth F site, F(5) is bonded in a distorted T-shaped 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 3-coordinate geometry to one Mg(1) and two equivalent Fe(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe8(OF)8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.808
_cell_length_b   9.892
_cell_length_c   3.048
_cell_angle_alpha   89.890
_cell_angle_beta   89.802
_cell_angle_gamma   89.542
_symmetry_Int_Tables_number   1
_cell_volume   295.642
_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  0.990  0.242  0.479  1.0
  Fe  Fe1  1  0.028  0.981  0.982  1.0
  Fe  Fe2  1  0.018  0.525  0.988  1.0
  Fe  Fe3  1  0.254  0.265  0.507  1.0
  Fe  Fe4  1  0.236  0.745  0.485  1.0
  Fe  Fe5  1  0.519  0.517  1.000  1.0
  Fe  Fe6  1  0.497  0.991  0.002  1.0
  Fe  Fe7  1  0.716  0.273  0.496  1.0
  Fe  Fe8  1  0.758  0.725  0.494  1.0
  O  O9  1  0.094  0.410  0.489  1.0
  O  O10  1  0.113  0.898  0.482  1.0
  O  O11  1  0.110  0.161  0.982  1.0
  O  O12  1  0.164  0.655  0.986  1.0
  O  O13  1  0.593  0.417  0.500  1.0
  O  O14  1  0.651  0.658  0.996  1.0
  O  O15  1  0.842  0.301  0.991  1.0
  O  O16  1  0.905  0.596  0.489  1.0
  F  F17  1  0.362  0.371  0.005  1.0
  F  F18  1  0.356  0.840  0.987  1.0
  F  F19  1  0.390  0.100  0.503  1.0
  F  F20  1  0.407  0.610  0.497  1.0
  F  F21  1  0.614  0.901  0.499  1.0
  F  F22  1  0.626  0.158  0.001  1.0
  F  F23  1  0.855  0.839  0.989  1.0
  F  F24  1  0.895  0.064  0.486  1.0
[/CIF]
.