The structure described by MgCr4O8 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(5), one O(6), and one O(7) atom. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form a mixture of distorted edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 35-60°. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 35-60°. In the third Cr site, Cr(3) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 35-63°. In the fourth Cr site, Cr(4) is bonded to one O(1), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 35-63°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Mg(1), one Cr(1), one Cr(2), and one Cr(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Cr(3) atom. In the third O site, O(3) is bonded to one Mg(1), one Cr(1), one Cr(2), and one Cr(3) atom to form a mixture of edge and corner-sharing OMgCr3 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Cr(4) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Cr(2), one Cr(3), and one Cr(4) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Cr(3), and one Cr(4) atom. In the seventh O site, O(7) is bonded to one Mg(1), one Cr(1), one Cr(3), and one Cr(4) atom to form a mixture of distorted edge and corner-sharing OMgCr3 trigonal pyramids. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(3), and one Cr(4) atom. is represented by the CIF card [CIF]
data_MgCr4O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.776
_cell_length_b   5.014
_cell_length_c   5.595
_cell_angle_alpha   94.598
_cell_angle_beta   87.516
_cell_angle_gamma   91.383
_symmetry_Int_Tables_number   1
_cell_volume   133.388
_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  0.035  0.076  0.505  1.0
  Cr  Cr1  1  0.526  0.277  0.648  1.0
  Cr  Cr2  1  0.020  0.738  0.859  1.0
  Cr  Cr3  1  0.498  0.731  0.338  1.0
  Cr  Cr4  1  0.996  0.268  0.111  1.0
  O  O5  1  0.820  0.094  0.829  1.0
  O  O6  1  0.753  0.579  0.595  1.0
  O  O7  1  0.327  0.905  0.641  1.0
  O  O8  1  0.254  0.422  0.880  1.0
  O  O9  1  0.195  0.915  0.151  1.0
  O  O10  1  0.257  0.410  0.392  1.0
  O  O11  1  0.695  0.092  0.347  1.0
  O  O12  1  0.764  0.581  0.097  1.0
[/CIF]
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The structure described by MgCr4O8 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(5), one O(6), and one O(7) atom. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form a mixture of distorted edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 35-60°. In the second Cr site, Cr(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 35-60°. In the third Cr site, Cr(3) is bonded to one O(2), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 35-63°. In the fourth Cr site, Cr(4) is bonded to one O(1), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form a mixture of edge and corner-sharing CrO6 octahedra. The corner-sharing octahedral tilt angles range from 35-63°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Mg(1), one Cr(1), one Cr(2), and one Cr(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Cr(3) atom. In the third O site, O(3) is bonded to one Mg(1), one Cr(1), one Cr(2), and one Cr(3) atom to form a mixture of edge and corner-sharing OMgCr3 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Cr(4) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Cr(2), one Cr(3), and one Cr(4) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Cr(3), and one Cr(4) atom. In the seventh O site, O(7) is bonded to one Mg(1), one Cr(1), one Cr(3), and one Cr(4) atom to form a mixture of distorted edge and corner-sharing OMgCr3 trigonal pyramids. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Cr(2), one Cr(3), and one Cr(4) atom. is represented by the CIF card [CIF]
data_MgCr4O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.776
_cell_length_b   5.014
_cell_length_c   5.595
_cell_angle_alpha   94.598
_cell_angle_beta   87.516
_cell_angle_gamma   91.383
_symmetry_Int_Tables_number   1
_cell_volume   133.388
_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  0.035  0.076  0.505  1.0
  Cr  Cr1  1  0.526  0.277  0.648  1.0
  Cr  Cr2  1  0.020  0.738  0.859  1.0
  Cr  Cr3  1  0.498  0.731  0.338  1.0
  Cr  Cr4  1  0.996  0.268  0.111  1.0
  O  O5  1  0.820  0.094  0.829  1.0
  O  O6  1  0.753  0.579  0.595  1.0
  O  O7  1  0.327  0.905  0.641  1.0
  O  O8  1  0.254  0.422  0.880  1.0
  O  O9  1  0.195  0.915  0.151  1.0
  O  O10  1  0.257  0.410  0.392  1.0
  O  O11  1  0.695  0.092  0.347  1.0
  O  O12  1  0.764  0.581  0.097  1.0
[/CIF]
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