The structure described by MgFe4(NiO4)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-6°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), and two equivalent O(1) atoms. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. 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 Fe(2)O6 octahedra. In the second Ni site, Ni(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-6°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), one Fe(2), one Ni(1), and one Ni(2) atom to form OMgFe2Ni2 square pyramids that share corners with five equivalent O(1)MgFe2Ni2 square pyramids, corners with three equivalent O(2)Fe3Ni tetrahedra,  a cornercorner with one O(3)MgFe3Ni trigonal bipyramid, edges with three equivalent O(1)MgFe2Ni2 square pyramids,  an edgeedge with one O(2)Fe3Ni tetrahedra, and edges with three equivalent O(3)MgFe3Ni trigonal bipyramids. In the second O site, O(2) is bonded to one Fe(1), two equivalent Fe(2), and one Ni(1) atom to form distorted OFe3Ni tetrahedra that share corners with six equivalent O(1)MgFe2Ni2 square pyramids, corners with three equivalent O(2)Fe3Ni tetrahedra, corners with three equivalent O(3)MgFe3Ni trigonal bipyramids, edges with two equivalent O(1)MgFe2Ni2 square pyramids, and  an edgeedge with one O(3)MgFe3Ni trigonal bipyramid. In the third O site, O(3) is bonded to one Mg(1), one Fe(1), two equivalent Fe(2), and one Ni(2) atom to form OMgFe3Ni trigonal bipyramids that share corners with two equivalent O(1)MgFe2Ni2 square pyramids, corners with three equivalent O(2)Fe3Ni tetrahedra, corners with four equivalent O(3)MgFe3Ni trigonal bipyramids, edges with six equivalent O(1)MgFe2Ni2 square pyramids, and  an edgeedge with one O(2)Fe3Ni tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe4(NiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.812
_cell_length_b   5.846
_cell_length_c   6.223
_cell_angle_alpha   61.985
_cell_angle_beta   63.044
_cell_angle_gamma   59.810
_symmetry_Int_Tables_number   1
_cell_volume   154.676
_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  0.125  0.125  0.625  1.0
  Fe  Fe1  1  0.967  0.974  0.086  1.0
  Fe  Fe2  1  0.283  0.276  0.164  1.0
  Fe  Fe3  1  0.625  0.125  0.625  1.0
  Fe  Fe4  1  0.625  0.625  0.625  1.0
  Ni  Ni5  1  0.125  0.625  0.625  1.0
  Ni  Ni6  1  0.625  0.625  0.125  1.0
  O  O7  1  0.381  0.365  0.390  1.0
  O  O8  1  0.417  0.390  0.803  1.0
  O  O9  1  0.381  0.864  0.390  1.0
  O  O10  1  0.862  0.371  0.397  1.0
  O  O11  1  0.388  0.879  0.853  1.0
  O  O12  1  0.869  0.386  0.860  1.0
  O  O13  1  0.833  0.860  0.447  1.0
  O  O14  1  0.869  0.885  0.860  1.0
[/CIF]
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The structure described by MgFe4(NiO4)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-6°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), and two equivalent O(1) atoms. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. 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 Fe(2)O6 octahedra. In the second Ni site, Ni(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-6°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), one Fe(2), one Ni(1), and one Ni(2) atom to form OMgFe2Ni2 square pyramids that share corners with five equivalent O(1)MgFe2Ni2 square pyramids, corners with three equivalent O(2)Fe3Ni tetrahedra,  a cornercorner with one O(3)MgFe3Ni trigonal bipyramid, edges with three equivalent O(1)MgFe2Ni2 square pyramids,  an edgeedge with one O(2)Fe3Ni tetrahedra, and edges with three equivalent O(3)MgFe3Ni trigonal bipyramids. In the second O site, O(2) is bonded to one Fe(1), two equivalent Fe(2), and one Ni(1) atom to form distorted OFe3Ni tetrahedra that share corners with six equivalent O(1)MgFe2Ni2 square pyramids, corners with three equivalent O(2)Fe3Ni tetrahedra, corners with three equivalent O(3)MgFe3Ni trigonal bipyramids, edges with two equivalent O(1)MgFe2Ni2 square pyramids, and  an edgeedge with one O(3)MgFe3Ni trigonal bipyramid. In the third O site, O(3) is bonded to one Mg(1), one Fe(1), two equivalent Fe(2), and one Ni(2) atom to form OMgFe3Ni trigonal bipyramids that share corners with two equivalent O(1)MgFe2Ni2 square pyramids, corners with three equivalent O(2)Fe3Ni tetrahedra, corners with four equivalent O(3)MgFe3Ni trigonal bipyramids, edges with six equivalent O(1)MgFe2Ni2 square pyramids, and  an edgeedge with one O(2)Fe3Ni tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe4(NiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.812
_cell_length_b   5.846
_cell_length_c   6.223
_cell_angle_alpha   61.985
_cell_angle_beta   63.044
_cell_angle_gamma   59.810
_symmetry_Int_Tables_number   1
_cell_volume   154.676
_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  0.125  0.125  0.625  1.0
  Fe  Fe1  1  0.967  0.974  0.086  1.0
  Fe  Fe2  1  0.283  0.276  0.164  1.0
  Fe  Fe3  1  0.625  0.125  0.625  1.0
  Fe  Fe4  1  0.625  0.625  0.625  1.0
  Ni  Ni5  1  0.125  0.625  0.625  1.0
  Ni  Ni6  1  0.625  0.625  0.125  1.0
  O  O7  1  0.381  0.365  0.390  1.0
  O  O8  1  0.417  0.390  0.803  1.0
  O  O9  1  0.381  0.864  0.390  1.0
  O  O10  1  0.862  0.371  0.397  1.0
  O  O11  1  0.388  0.879  0.853  1.0
  O  O12  1  0.869  0.386  0.860  1.0
  O  O13  1  0.833  0.860  0.447  1.0
  O  O14  1  0.869  0.885  0.860  1.0
[/CIF]
.