The compound described by MgCr4O8 crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, edges with two equivalent Cr(4)O6 octahedra, and faces with two equivalent Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-51°. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Cr(2)O6 octahedra, corners with four equivalent Cr(4)O6 octahedra, and edges with two equivalent Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-53°. In the second Cr site, Cr(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, corners with four equivalent Cr(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Cr(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-53°. In the third Cr site, Cr(3) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with four equivalent Cr(2)O6 octahedra, corners with four equivalent Cr(4)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-50°. In the fourth Cr site, Cr(4) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, corners with four equivalent Cr(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-50°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Cr(4) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Cr(2), and one Cr(3) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(2), one Cr(3), and one Cr(4) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Cr(3), and one Cr(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCr4O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.797
_cell_length_b   4.969
_cell_length_c   5.595
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.396
_symmetry_Int_Tables_number   1
_cell_volume   133.353
_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  0.000  0.750  0.391  1.0
  Cr  Cr1  1  0.500  0.250  0.647  1.0
  Cr  Cr2  1  1.000  0.750  0.864  1.0
  Cr  Cr3  1  0.500  0.750  0.349  1.0
  Cr  Cr4  1  0.000  0.250  0.137  1.0
  O  O5  1  0.783  0.086  0.882  1.0
  O  O6  1  0.730  0.588  0.615  1.0
  O  O7  1  0.270  0.912  0.615  1.0
  O  O8  1  0.217  0.414  0.882  1.0
  O  O9  1  0.222  0.917  0.122  1.0
  O  O10  1  0.258  0.420  0.377  1.0
  O  O11  1  0.742  0.080  0.377  1.0
  O  O12  1  0.778  0.583  0.122  1.0
[/CIF]
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The compound described by MgCr4O8 crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, edges with two equivalent Cr(2)O6 octahedra, edges with two equivalent Cr(4)O6 octahedra, and faces with two equivalent Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-51°. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Cr(2)O6 octahedra, corners with four equivalent Cr(4)O6 octahedra, and edges with two equivalent Cr(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-53°. In the second Cr site, Cr(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CrO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, corners with four equivalent Cr(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Cr(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-53°. In the third Cr site, Cr(3) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with four equivalent Cr(2)O6 octahedra, corners with four equivalent Cr(4)O6 octahedra, edges with two equivalent Cr(1)O6 octahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-50°. In the fourth Cr site, Cr(4) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with four equivalent Cr(1)O6 octahedra, corners with four equivalent Cr(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Cr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-50°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Cr(1), one Cr(2), and one Cr(4) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Cr(2), and one Cr(3) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Cr(2), one Cr(3), and one Cr(4) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Cr(1), one Cr(3), and one Cr(4) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCr4O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.797
_cell_length_b   4.969
_cell_length_c   5.595
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.396
_symmetry_Int_Tables_number   1
_cell_volume   133.353
_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  0.000  0.750  0.391  1.0
  Cr  Cr1  1  0.500  0.250  0.647  1.0
  Cr  Cr2  1  1.000  0.750  0.864  1.0
  Cr  Cr3  1  0.500  0.750  0.349  1.0
  Cr  Cr4  1  0.000  0.250  0.137  1.0
  O  O5  1  0.783  0.086  0.882  1.0
  O  O6  1  0.730  0.588  0.615  1.0
  O  O7  1  0.270  0.912  0.615  1.0
  O  O8  1  0.217  0.414  0.882  1.0
  O  O9  1  0.222  0.917  0.122  1.0
  O  O10  1  0.258  0.420  0.377  1.0
  O  O11  1  0.742  0.080  0.377  1.0
  O  O12  1  0.778  0.583  0.122  1.0
[/CIF]
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