The material described by MgCu2(O2F)2 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(2), two equivalent O(4), one F(2), and two equivalent F(1) atoms to form MgO3F3 octahedra that share  a cornercorner with one Cu(2)O3F tetrahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with four equivalent Cu(1)O3F3 octahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(4), two equivalent O(2), one F(1), and two equivalent F(2) atoms to form distorted CuO3F3 octahedra that share corners with two equivalent Cu(2)O3F tetrahedra, edges with two equivalent Cu(1)O3F3 octahedra, and edges with four equivalent Mg(1)O3F3 octahedra. In the second Cu site, Cu(2) is bonded to one O(3), two equivalent O(1), and one F(2) atom to form CuO3F tetrahedra that share  a cornercorner with one Mg(1)O3F3 octahedra, corners with two equivalent Cu(1)O3F3 octahedra,  a cornercorner with one O(2)MgCu2O tetrahedra, corners with two equivalent Cu(2)O3F tetrahedra, and corners with two equivalent O(4)Mg2CuO tetrahedra. The corner-sharing octahedral tilt angles range from 49-70°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cu(2) and one O(4) atom. In the second O site, O(2) is bonded to one Mg(1), two equivalent Cu(1), and one O(3) atom to form distorted OMgCu2O tetrahedra that share  a cornercorner with one Cu(2)O3F tetrahedra, corners with two equivalent O(2)MgCu2O tetrahedra, and corners with four equivalent O(4)Mg2CuO tetrahedra. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Cu(2) and one O(2) atom. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Cu(1), and one O(1) atom to form distorted OMg2CuO tetrahedra that share corners with two equivalent Cu(2)O3F tetrahedra, corners with two equivalent O(4)Mg2CuO tetrahedra, and corners with four equivalent O(2)MgCu2O tetrahedra. There are two inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Mg(1) and one Cu(1) atom. In the second F site, F(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Cu(2), and two equivalent Cu(1) atoms. is represented by the CIF file [CIF]
data_MgCu2(O2F)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.237
_cell_length_b   5.438
_cell_length_c   6.440
_cell_angle_alpha   77.944
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   110.847
_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  0.500  0.221  0.189  1.0
  Cu  Cu1  1  0.000  0.702  0.255  1.0
  Cu  Cu2  1  0.500  0.093  0.703  1.0
  O  O3  1  0.000  0.963  0.604  1.0
  O  O4  1  0.500  0.506  0.375  1.0
  O  O5  1  0.500  0.443  0.598  1.0
  O  O6  1  0.000  0.017  0.372  1.0
  F  F7  1  0.000  0.396  0.051  1.0
  F  F8  1  0.500  0.945  0.031  1.0
[/CIF]
.
The material described by MgCu2(O2F)2 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(2), two equivalent O(4), one F(2), and two equivalent F(1) atoms to form MgO3F3 octahedra that share  a cornercorner with one Cu(2)O3F tetrahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with four equivalent Cu(1)O3F3 octahedra. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(4), two equivalent O(2), one F(1), and two equivalent F(2) atoms to form distorted CuO3F3 octahedra that share corners with two equivalent Cu(2)O3F tetrahedra, edges with two equivalent Cu(1)O3F3 octahedra, and edges with four equivalent Mg(1)O3F3 octahedra. In the second Cu site, Cu(2) is bonded to one O(3), two equivalent O(1), and one F(2) atom to form CuO3F tetrahedra that share  a cornercorner with one Mg(1)O3F3 octahedra, corners with two equivalent Cu(1)O3F3 octahedra,  a cornercorner with one O(2)MgCu2O tetrahedra, corners with two equivalent Cu(2)O3F tetrahedra, and corners with two equivalent O(4)Mg2CuO tetrahedra. The corner-sharing octahedral tilt angles range from 49-70°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Cu(2) and one O(4) atom. In the second O site, O(2) is bonded to one Mg(1), two equivalent Cu(1), and one O(3) atom to form distorted OMgCu2O tetrahedra that share  a cornercorner with one Cu(2)O3F tetrahedra, corners with two equivalent O(2)MgCu2O tetrahedra, and corners with four equivalent O(4)Mg2CuO tetrahedra. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Cu(2) and one O(2) atom. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Cu(1), and one O(1) atom to form distorted OMg2CuO tetrahedra that share corners with two equivalent Cu(2)O3F tetrahedra, corners with two equivalent O(4)Mg2CuO tetrahedra, and corners with four equivalent O(2)MgCu2O tetrahedra. There are two inequivalent F sites. In the first F site, F(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Mg(1) and one Cu(1) atom. In the second F site, F(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Cu(2), and two equivalent Cu(1) atoms. is represented by the CIF file [CIF]
data_MgCu2(O2F)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.237
_cell_length_b   5.438
_cell_length_c   6.440
_cell_angle_alpha   77.944
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   110.847
_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  0.500  0.221  0.189  1.0
  Cu  Cu1  1  0.000  0.702  0.255  1.0
  Cu  Cu2  1  0.500  0.093  0.703  1.0
  O  O3  1  0.000  0.963  0.604  1.0
  O  O4  1  0.500  0.506  0.375  1.0
  O  O5  1  0.500  0.443  0.598  1.0
  O  O6  1  0.000  0.017  0.372  1.0
  F  F7  1  0.000  0.396  0.051  1.0
  F  F8  1  0.500  0.945  0.031  1.0
[/CIF]
.