The compound described by MgFe4NiO8 is Spinel-derived structured and crystallizes in the trigonal R3m space group. Mg(1) is bonded to one O(3) and three equivalent O(4) atoms to form MgO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with nine equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-59°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(1) and three equivalent O(2) atoms to form FeO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with nine equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-58°. Ni(1) is bonded to three equivalent O(2) and three equivalent O(4) atoms to form NiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, and edges with six equivalent Fe(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Fe(2) and three equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing OFe4 trigonal pyramids. In the second O site, O(2) is bonded to one Fe(2), two equivalent Fe(1), and one Ni(1) atom to form distorted OFe3Ni trigonal pyramids that share  a cornercorner with one O(1)Fe4 trigonal pyramid, corners with two equivalent O(2)Fe3Ni trigonal pyramids,  an edgeedge with one O(1)Fe4 trigonal pyramid, and edges with two equivalent O(2)Fe3Ni trigonal pyramids. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1) and three equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Fe(1), and one Ni(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe4NiO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.020
_cell_length_b   6.020
_cell_length_c   6.020
_cell_angle_alpha   60.165
_cell_angle_beta   60.165
_cell_angle_gamma   60.165
_symmetry_Int_Tables_number   1
_cell_volume   154.821
_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  0.876  0.876  0.876  1.0
  Fe  Fe1  1  0.992  0.502  0.502  1.0
  Fe  Fe2  1  0.502  0.502  0.992  1.0
  Fe  Fe3  1  0.502  0.992  0.502  1.0
  Fe  Fe4  1  0.123  0.123  0.123  1.0
  Ni  Ni5  1  0.501  0.501  0.501  1.0
  O  O6  1  0.257  0.257  0.257  1.0
  O  O7  1  0.731  0.254  0.254  1.0
  O  O8  1  0.254  0.254  0.731  1.0
  O  O9  1  0.254  0.731  0.254  1.0
  O  O10  1  0.741  0.741  0.741  1.0
  O  O11  1  0.278  0.745  0.745  1.0
  O  O12  1  0.745  0.745  0.278  1.0
  O  O13  1  0.745  0.278  0.745  1.0
[/CIF]
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The compound described by MgFe4NiO8 is Spinel-derived structured and crystallizes in the trigonal R3m space group. Mg(1) is bonded to one O(3) and three equivalent O(4) atoms to form MgO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with nine equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-59°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. In the second Fe site, Fe(2) is bonded to one O(1) and three equivalent O(2) atoms to form FeO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with nine equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-58°. Ni(1) is bonded to three equivalent O(2) and three equivalent O(4) atoms to form NiO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra, and edges with six equivalent Fe(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Fe(2) and three equivalent Fe(1) atoms to form a mixture of distorted corner and edge-sharing OFe4 trigonal pyramids. In the second O site, O(2) is bonded to one Fe(2), two equivalent Fe(1), and one Ni(1) atom to form distorted OFe3Ni trigonal pyramids that share  a cornercorner with one O(1)Fe4 trigonal pyramid, corners with two equivalent O(2)Fe3Ni trigonal pyramids,  an edgeedge with one O(1)Fe4 trigonal pyramid, and edges with two equivalent O(2)Fe3Ni trigonal pyramids. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1) and three equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Fe(1), and one Ni(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgFe4NiO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.020
_cell_length_b   6.020
_cell_length_c   6.020
_cell_angle_alpha   60.165
_cell_angle_beta   60.165
_cell_angle_gamma   60.165
_symmetry_Int_Tables_number   1
_cell_volume   154.821
_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  0.876  0.876  0.876  1.0
  Fe  Fe1  1  0.992  0.502  0.502  1.0
  Fe  Fe2  1  0.502  0.502  0.992  1.0
  Fe  Fe3  1  0.502  0.992  0.502  1.0
  Fe  Fe4  1  0.123  0.123  0.123  1.0
  Ni  Ni5  1  0.501  0.501  0.501  1.0
  O  O6  1  0.257  0.257  0.257  1.0
  O  O7  1  0.731  0.254  0.254  1.0
  O  O8  1  0.254  0.254  0.731  1.0
  O  O9  1  0.254  0.731  0.254  1.0
  O  O10  1  0.741  0.741  0.741  1.0
  O  O11  1  0.278  0.745  0.745  1.0
  O  O12  1  0.745  0.745  0.278  1.0
  O  O13  1  0.745  0.278  0.745  1.0
[/CIF]
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