The crystal structure described by MgFe4(NiO4)2 is Aluminum carbonitride-derived structured and crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(5) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(4), one O(6), and two equivalent O(5) atoms to form distorted FeO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-72°. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form FeO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-75°. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(6) atom. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(5) atoms to form NiO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, and edges with two equivalent Ni(2)O6 octahedra. In the second Ni site, Ni(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form NiO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, and edges with two equivalent Ni(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Fe(2), one Fe(3), one Ni(1), and one Ni(2) atom. In the second O site, O(2) is bonded to one Mg(1), one Fe(2), two equivalent Fe(3), and one Ni(1) atom to form distorted OMgFe3Ni square pyramids that share corners with two equivalent O(4)Fe3Ni tetrahedra, corners with three equivalent O(6)Fe3Ni tetrahedra, corners with four equivalent O(5)MgFeNi2 tetrahedra,  a cornercorner with one O(3)MgFe3Ni trigonal bipyramid, and  a faceface with one O(3)MgFe3Ni trigonal bipyramid. In the third O site, O(3) is bonded to one Mg(1), one Fe(2), two equivalent Fe(3), and one Ni(2) atom to form distorted OMgFe3Ni trigonal bipyramids that share  a cornercorner with one O(2)MgFe3Ni square pyramid, corners with two equivalent O(6)Fe3Ni tetrahedra, corners with three equivalent O(4)Fe3Ni tetrahedra, corners with four equivalent O(5)MgFeNi2 tetrahedra, and  a faceface with one O(2)MgFe3Ni square pyramid. In the fourth O site, O(4) is bonded to one Fe(1), two equivalent Fe(3), and one Ni(2) atom to form OFe3Ni tetrahedra that share corners with two equivalent O(2)MgFe3Ni square pyramids,  a cornercorner with one O(6)Fe3Ni tetrahedra, corners with four equivalent O(5)MgFeNi2 tetrahedra, corners with three equivalent O(3)MgFe3Ni trigonal bipyramids, and  an edgeedge with one O(6)Fe3Ni tetrahedra. In the fifth O site, O(5) is bonded to one Mg(1), one Fe(1), one Ni(1), and one Ni(2) atom to form distorted OMgFeNi2 tetrahedra that share corners with two equivalent O(2)MgFe3Ni square pyramids, corners with two equivalent O(4)Fe3Ni tetrahedra, corners with two equivalent O(6)Fe3Ni tetrahedra, corners with two equivalent O(3)MgFe3Ni trigonal bipyramids, and edges with two equivalent O(5)MgFeNi2 tetrahedra. In the sixth O site, O(6) is bonded to one Fe(1), two equivalent Fe(3), and one Ni(1) atom to form OFe3Ni tetrahedra that share corners with three equivalent O(2)MgFe3Ni square pyramids,  a cornercorner with one O(4)Fe3Ni tetrahedra, corners with four equivalent O(5)MgFeNi2 tetrahedra, corners with two equivalent O(3)MgFe3Ni trigonal bipyramids, and  an edgeedge with one O(4)Fe3Ni tetrahedra. is represented by the CIF card [CIF]
data_MgFe4(NiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.275
_cell_length_b   5.864
_cell_length_c   6.270
_cell_angle_alpha   62.118
_cell_angle_beta   59.621
_cell_angle_gamma   62.141
_symmetry_Int_Tables_number   1
_cell_volume   167.668
_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  0.782  0.217  0.784  1.0
  Fe  Fe1  1  0.071  0.929  0.071  1.0
  Fe  Fe2  1  0.205  0.294  0.206  1.0
  Fe  Fe3  1  0.559  0.159  0.558  1.0
  Fe  Fe4  1  0.559  0.724  0.558  1.0
  Ni  Ni5  1  0.120  0.621  0.638  1.0
  Ni  Ni6  1  0.638  0.622  0.119  1.0
  O  O7  1  0.353  0.412  0.353  1.0
  O  O8  1  0.411  0.385  0.820  1.0
  O  O9  1  0.353  0.883  0.353  1.0
  O  O10  1  0.819  0.385  0.411  1.0
  O  O11  1  0.436  0.849  0.865  1.0
  O  O12  1  0.925  0.322  0.925  1.0
  O  O13  1  0.866  0.849  0.436  1.0
  O  O14  1  0.925  0.828  0.925  1.0
[/CIF]
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The crystal structure described by MgFe4(NiO4)2 is Aluminum carbonitride-derived structured and crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), and two equivalent O(5) atoms. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(4), one O(6), and two equivalent O(5) atoms to form distorted FeO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-72°. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form FeO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-75°. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(6) atom. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(5) atoms to form NiO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, and edges with two equivalent Ni(2)O6 octahedra. In the second Ni site, Ni(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form NiO6 octahedra that share corners with three equivalent Fe(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, and edges with two equivalent Ni(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Fe(2), one Fe(3), one Ni(1), and one Ni(2) atom. In the second O site, O(2) is bonded to one Mg(1), one Fe(2), two equivalent Fe(3), and one Ni(1) atom to form distorted OMgFe3Ni square pyramids that share corners with two equivalent O(4)Fe3Ni tetrahedra, corners with three equivalent O(6)Fe3Ni tetrahedra, corners with four equivalent O(5)MgFeNi2 tetrahedra,  a cornercorner with one O(3)MgFe3Ni trigonal bipyramid, and  a faceface with one O(3)MgFe3Ni trigonal bipyramid. In the third O site, O(3) is bonded to one Mg(1), one Fe(2), two equivalent Fe(3), and one Ni(2) atom to form distorted OMgFe3Ni trigonal bipyramids that share  a cornercorner with one O(2)MgFe3Ni square pyramid, corners with two equivalent O(6)Fe3Ni tetrahedra, corners with three equivalent O(4)Fe3Ni tetrahedra, corners with four equivalent O(5)MgFeNi2 tetrahedra, and  a faceface with one O(2)MgFe3Ni square pyramid. In the fourth O site, O(4) is bonded to one Fe(1), two equivalent Fe(3), and one Ni(2) atom to form OFe3Ni tetrahedra that share corners with two equivalent O(2)MgFe3Ni square pyramids,  a cornercorner with one O(6)Fe3Ni tetrahedra, corners with four equivalent O(5)MgFeNi2 tetrahedra, corners with three equivalent O(3)MgFe3Ni trigonal bipyramids, and  an edgeedge with one O(6)Fe3Ni tetrahedra. In the fifth O site, O(5) is bonded to one Mg(1), one Fe(1), one Ni(1), and one Ni(2) atom to form distorted OMgFeNi2 tetrahedra that share corners with two equivalent O(2)MgFe3Ni square pyramids, corners with two equivalent O(4)Fe3Ni tetrahedra, corners with two equivalent O(6)Fe3Ni tetrahedra, corners with two equivalent O(3)MgFe3Ni trigonal bipyramids, and edges with two equivalent O(5)MgFeNi2 tetrahedra. In the sixth O site, O(6) is bonded to one Fe(1), two equivalent Fe(3), and one Ni(1) atom to form OFe3Ni tetrahedra that share corners with three equivalent O(2)MgFe3Ni square pyramids,  a cornercorner with one O(4)Fe3Ni tetrahedra, corners with four equivalent O(5)MgFeNi2 tetrahedra, corners with two equivalent O(3)MgFe3Ni trigonal bipyramids, and  an edgeedge with one O(4)Fe3Ni tetrahedra. is represented by the CIF card [CIF]
data_MgFe4(NiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.275
_cell_length_b   5.864
_cell_length_c   6.270
_cell_angle_alpha   62.118
_cell_angle_beta   59.621
_cell_angle_gamma   62.141
_symmetry_Int_Tables_number   1
_cell_volume   167.668
_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  0.782  0.217  0.784  1.0
  Fe  Fe1  1  0.071  0.929  0.071  1.0
  Fe  Fe2  1  0.205  0.294  0.206  1.0
  Fe  Fe3  1  0.559  0.159  0.558  1.0
  Fe  Fe4  1  0.559  0.724  0.558  1.0
  Ni  Ni5  1  0.120  0.621  0.638  1.0
  Ni  Ni6  1  0.638  0.622  0.119  1.0
  O  O7  1  0.353  0.412  0.353  1.0
  O  O8  1  0.411  0.385  0.820  1.0
  O  O9  1  0.353  0.883  0.353  1.0
  O  O10  1  0.819  0.385  0.411  1.0
  O  O11  1  0.436  0.849  0.865  1.0
  O  O12  1  0.925  0.322  0.925  1.0
  O  O13  1  0.866  0.849  0.436  1.0
  O  O14  1  0.925  0.828  0.925  1.0
[/CIF]
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