The material described by MgCr3FeAlO8 is Spinel-derived structured and crystallizes in the trigonal R3m space group. Mg(1) is bonded to one O(4) and three equivalent O(3) atoms to form MgO4 tetrahedra that share corners with three equivalent Al(1)O6 octahedra and corners with nine equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-61°. Cr(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. Fe(1) is bonded to one O(2) and three equivalent O(1) atoms to form FeO4 tetrahedra that share corners with three equivalent Al(1)O6 octahedra and corners with nine equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. Al(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form AlO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, and edges with six equivalent Cr(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(1), one Fe(1), and one Al(1) atom. In the second O site, O(2) is bonded to three equivalent Cr(1) and one Fe(1) atom to form distorted corner-sharing OCr3Fe trigonal pyramids. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Cr(1), and one Al(1) atom. In the fourth O site, O(4) is bonded to one Mg(1) and three equivalent Cr(1) atoms to form distorted corner-sharing OMgCr3 trigonal pyramids. is represented by the CIF file [CIF]
data_MgAlCr3FeO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.911
_cell_length_b   5.911
_cell_length_c   5.911
_cell_angle_alpha   61.043
_cell_angle_beta   61.043
_cell_angle_gamma   61.043
_symmetry_Int_Tables_number   1
_cell_volume   149.481
_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  0.124  0.124  0.124  1.0
  Al  Al1  1  0.499  0.499  0.499  1.0
  Cr  Cr2  1  0.001  0.500  0.500  1.0
  Cr  Cr3  1  0.500  0.500  0.001  1.0
  Cr  Cr4  1  0.500  0.001  0.500  1.0
  Fe  Fe5  1  0.876  0.876  0.876  1.0
  O  O6  1  0.291  0.729  0.729  1.0
  O  O7  1  0.729  0.729  0.291  1.0
  O  O8  1  0.729  0.291  0.729  1.0
  O  O9  1  0.740  0.740  0.740  1.0
  O  O10  1  0.714  0.268  0.268  1.0
  O  O11  1  0.268  0.268  0.714  1.0
  O  O12  1  0.268  0.714  0.268  1.0
  O  O13  1  0.261  0.261  0.261  1.0
[/CIF]
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The material described by MgCr3FeAlO8 is Spinel-derived structured and crystallizes in the trigonal R3m space group. Mg(1) is bonded to one O(4) and three equivalent O(3) atoms to form MgO4 tetrahedra that share corners with three equivalent Al(1)O6 octahedra and corners with nine equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-61°. Cr(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and edges with four equivalent Cr(1)O6 octahedra. Fe(1) is bonded to one O(2) and three equivalent O(1) atoms to form FeO4 tetrahedra that share corners with three equivalent Al(1)O6 octahedra and corners with nine equivalent Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. Al(1) is bonded to three equivalent O(1) and three equivalent O(3) atoms to form AlO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, and edges with six equivalent Cr(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Cr(1), one Fe(1), and one Al(1) atom. In the second O site, O(2) is bonded to three equivalent Cr(1) and one Fe(1) atom to form distorted corner-sharing OCr3Fe trigonal pyramids. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Cr(1), and one Al(1) atom. In the fourth O site, O(4) is bonded to one Mg(1) and three equivalent Cr(1) atoms to form distorted corner-sharing OMgCr3 trigonal pyramids. is represented by the CIF file [CIF]
data_MgAlCr3FeO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.911
_cell_length_b   5.911
_cell_length_c   5.911
_cell_angle_alpha   61.043
_cell_angle_beta   61.043
_cell_angle_gamma   61.043
_symmetry_Int_Tables_number   1
_cell_volume   149.481
_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  0.124  0.124  0.124  1.0
  Al  Al1  1  0.499  0.499  0.499  1.0
  Cr  Cr2  1  0.001  0.500  0.500  1.0
  Cr  Cr3  1  0.500  0.500  0.001  1.0
  Cr  Cr4  1  0.500  0.001  0.500  1.0
  Fe  Fe5  1  0.876  0.876  0.876  1.0
  O  O6  1  0.291  0.729  0.729  1.0
  O  O7  1  0.729  0.729  0.291  1.0
  O  O8  1  0.729  0.291  0.729  1.0
  O  O9  1  0.740  0.740  0.740  1.0
  O  O10  1  0.714  0.268  0.268  1.0
  O  O11  1  0.268  0.268  0.714  1.0
  O  O12  1  0.268  0.714  0.268  1.0
  O  O13  1  0.261  0.261  0.261  1.0
[/CIF]
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