The compound described by MgCr2Mn2O8 crystallizes in the orthorhombic Amm2 space group. Mg(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra, corners with two equivalent Cr(2)O4 tetrahedra, and  an edgeedge with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-68°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-58°. In the second Cr site, Cr(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form CrO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. Mn(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra, and edges with two equivalent Mn(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one Mn(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one Cr(2), and one Mn(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Cr(1), and two equivalent Mn(1) atoms to form distorted edge-sharing OMgMn2Cr tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2) and two equivalent Mn(1) atoms. is represented by the CIF file [CIF]
data_MgMn2Cr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.262
_cell_length_b   5.262
_cell_length_c   6.467
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   113.433
_symmetry_Int_Tables_number   1
_cell_volume   164.277
_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  0.340  0.660  0.750  1.0
  Mn  Mn1  1  1.000  0.000  0.495  1.0
  Mn  Mn2  1  1.000  0.000  0.005  1.0
  Cr  Cr3  1  0.656  0.344  0.750  1.0
  Cr  Cr4  1  0.359  0.641  0.250  1.0
  O  O5  1  0.759  0.241  0.535  1.0
  O  O6  1  0.242  0.758  0.474  1.0
  O  O7  1  0.759  0.241  0.965  1.0
  O  O8  1  0.242  0.758  0.026  1.0
  O  O9  1  0.749  0.722  0.750  1.0
  O  O10  1  0.717  0.787  0.250  1.0
  O  O11  1  0.213  0.283  0.250  1.0
  O  O12  1  0.278  0.251  0.750  1.0
[/CIF]
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The compound described by MgCr2Mn2O8 crystallizes in the orthorhombic Amm2 space group. Mg(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form distorted MgO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra, corners with two equivalent Cr(2)O4 tetrahedra, and  an edgeedge with one Cr(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 66-68°. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form CrO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-58°. In the second Cr site, Cr(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form CrO4 tetrahedra that share corners with six equivalent Mn(1)O6 octahedra and corners with two equivalent Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. Mn(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent O(4) atoms to form MnO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Cr(1)O4 tetrahedra, corners with three equivalent Cr(2)O4 tetrahedra, and edges with two equivalent Mn(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cr(1) and one Mn(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Mg(1), one Cr(2), and one Mn(1) atom. In the third O site, O(3) is bonded to one Mg(1), one Cr(1), and two equivalent Mn(1) atoms to form distorted edge-sharing OMgMn2Cr tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Cr(2) and two equivalent Mn(1) atoms. is represented by the CIF file [CIF]
data_MgMn2Cr2O8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.262
_cell_length_b   5.262
_cell_length_c   6.467
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   113.433
_symmetry_Int_Tables_number   1
_cell_volume   164.277
_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  0.340  0.660  0.750  1.0
  Mn  Mn1  1  1.000  0.000  0.495  1.0
  Mn  Mn2  1  1.000  0.000  0.005  1.0
  Cr  Cr3  1  0.656  0.344  0.750  1.0
  Cr  Cr4  1  0.359  0.641  0.250  1.0
  O  O5  1  0.759  0.241  0.535  1.0
  O  O6  1  0.242  0.758  0.474  1.0
  O  O7  1  0.759  0.241  0.965  1.0
  O  O8  1  0.242  0.758  0.026  1.0
  O  O9  1  0.749  0.722  0.750  1.0
  O  O10  1  0.717  0.787  0.250  1.0
  O  O11  1  0.213  0.283  0.250  1.0
  O  O12  1  0.278  0.251  0.750  1.0
[/CIF]
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