The material structure described by MgFe2(NiO2)4 crystallizes in the trigonal R-3m space group. Mg(1) is bonded to six equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Ni(2)O6 octahedra and edges with six equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 2°. Fe(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2) and three equivalent O(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. In the second Ni site, Ni(2) is bonded to six equivalent O(1) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra and edges with six equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), one Ni(2), and two equivalent Ni(1) atoms to form OMgFeNi3 square pyramids that share corners with six equivalent O(1)MgFeNi3 square pyramids, corners with three equivalent O(2)FeNi3 tetrahedra, edges with six equivalent O(1)MgFeNi3 square pyramids, and  an edgeedge with one O(2)FeNi3 tetrahedra. In the second O site, O(2) is bonded to one Fe(1) and three equivalent Ni(1) atoms to form distorted OFeNi3 tetrahedra that share corners with nine equivalent O(1)MgFeNi3 square pyramids, corners with three equivalent O(2)FeNi3 tetrahedra, and edges with three equivalent O(1)MgFeNi3 square pyramids. is represented by the CIF file [CIF]
data_MgFe2(NiO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.870
_cell_length_b   6.222
_cell_length_c   5.870
_cell_angle_alpha   61.854
_cell_angle_beta   60.000
_cell_angle_gamma   61.844
_symmetry_Int_Tables_number   1
_cell_volume   155.675
_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  0.000  0.500  0.000  1.0
  Fe  Fe1  1  0.154  0.039  0.154  1.0
  Fe  Fe2  1  0.846  0.961  0.846  1.0
  Ni  Ni3  1  0.500  0.500  0.000  1.0
  Ni  Ni4  1  0.000  0.500  0.500  1.0
  Ni  Ni5  1  0.500  0.000  0.500  1.0
  Ni  Ni6  1  0.500  0.500  0.500  1.0
  O  O7  1  0.240  0.753  0.753  1.0
  O  O8  1  0.271  0.688  0.271  1.0
  O  O9  1  0.760  0.247  0.247  1.0
  O  O10  1  0.247  0.247  0.247  1.0
  O  O11  1  0.247  0.247  0.760  1.0
  O  O12  1  0.729  0.312  0.729  1.0
  O  O13  1  0.753  0.753  0.240  1.0
  O  O14  1  0.753  0.753  0.753  1.0
[/CIF]
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The material structure described by MgFe2(NiO2)4 crystallizes in the trigonal R-3m space group. Mg(1) is bonded to six equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Ni(2)O6 octahedra and edges with six equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 2°. Fe(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2) and three equivalent O(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with four equivalent Ni(1)O6 octahedra. In the second Ni site, Ni(2) is bonded to six equivalent O(1) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra and edges with six equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), one Ni(2), and two equivalent Ni(1) atoms to form OMgFeNi3 square pyramids that share corners with six equivalent O(1)MgFeNi3 square pyramids, corners with three equivalent O(2)FeNi3 tetrahedra, edges with six equivalent O(1)MgFeNi3 square pyramids, and  an edgeedge with one O(2)FeNi3 tetrahedra. In the second O site, O(2) is bonded to one Fe(1) and three equivalent Ni(1) atoms to form distorted OFeNi3 tetrahedra that share corners with nine equivalent O(1)MgFeNi3 square pyramids, corners with three equivalent O(2)FeNi3 tetrahedra, and edges with three equivalent O(1)MgFeNi3 square pyramids. is represented by the CIF file [CIF]
data_MgFe2(NiO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.870
_cell_length_b   6.222
_cell_length_c   5.870
_cell_angle_alpha   61.854
_cell_angle_beta   60.000
_cell_angle_gamma   61.844
_symmetry_Int_Tables_number   1
_cell_volume   155.675
_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  0.000  0.500  0.000  1.0
  Fe  Fe1  1  0.154  0.039  0.154  1.0
  Fe  Fe2  1  0.846  0.961  0.846  1.0
  Ni  Ni3  1  0.500  0.500  0.000  1.0
  Ni  Ni4  1  0.000  0.500  0.500  1.0
  Ni  Ni5  1  0.500  0.000  0.500  1.0
  Ni  Ni6  1  0.500  0.500  0.500  1.0
  O  O7  1  0.240  0.753  0.753  1.0
  O  O8  1  0.271  0.688  0.271  1.0
  O  O9  1  0.760  0.247  0.247  1.0
  O  O10  1  0.247  0.247  0.247  1.0
  O  O11  1  0.247  0.247  0.760  1.0
  O  O12  1  0.729  0.312  0.729  1.0
  O  O13  1  0.753  0.753  0.240  1.0
  O  O14  1  0.753  0.753  0.753  1.0
[/CIF]
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