The structure described by MgCr2(BiO4)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted MgO6 octahedra that share corners with two equivalent Cr(1)O4 tetrahedra and edges with two equivalent Cr(1)O4 tetrahedra. Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CrO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 56°. Bi(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), and two equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Cr(1), and one Bi(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Cr(1), and one Bi(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Cr(1) and two equivalent Bi(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one Cr(1), and one Bi(1) atom. is represented by the CIF file [CIF]
data_MgCr2(BiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.476
_cell_length_b   6.123
_cell_length_c   6.123
_cell_angle_alpha   103.370
_cell_angle_beta   107.472
_cell_angle_gamma   115.252
_symmetry_Int_Tables_number   1
_cell_volume   190.433
_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  0.500  0.740  0.240  1.0
  Cr  Cr1  1  0.368  0.610  0.713  1.0
  Cr  Cr2  1  0.632  0.345  0.242  1.0
  Bi  Bi3  1  0.063  0.865  0.260  1.0
  Bi  Bi4  1  0.937  0.197  0.802  1.0
  O  O5  1  0.193  0.627  0.909  1.0
  O  O6  1  0.345  0.756  0.496  1.0
  O  O7  1  0.193  0.253  0.591  1.0
  O  O8  1  0.677  0.805  0.984  1.0
  O  O9  1  0.323  0.307  0.128  1.0
  O  O10  1  0.807  0.716  0.434  1.0
  O  O11  1  0.655  0.151  0.412  1.0
  O  O12  1  0.806  0.398  0.060  1.0
[/CIF]
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The structure described by MgCr2(BiO4)2 crystallizes in the monoclinic C2 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted MgO6 octahedra that share corners with two equivalent Cr(1)O4 tetrahedra and edges with two equivalent Cr(1)O4 tetrahedra. Cr(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form CrO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles are 56°. Bi(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), and two equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Cr(1), and one Bi(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Cr(1), and one Bi(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Cr(1) and two equivalent Bi(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Mg(1), one Cr(1), and one Bi(1) atom. is represented by the CIF file [CIF]
data_MgCr2(BiO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.476
_cell_length_b   6.123
_cell_length_c   6.123
_cell_angle_alpha   103.370
_cell_angle_beta   107.472
_cell_angle_gamma   115.252
_symmetry_Int_Tables_number   1
_cell_volume   190.433
_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  0.500  0.740  0.240  1.0
  Cr  Cr1  1  0.368  0.610  0.713  1.0
  Cr  Cr2  1  0.632  0.345  0.242  1.0
  Bi  Bi3  1  0.063  0.865  0.260  1.0
  Bi  Bi4  1  0.937  0.197  0.802  1.0
  O  O5  1  0.193  0.627  0.909  1.0
  O  O6  1  0.345  0.756  0.496  1.0
  O  O7  1  0.193  0.253  0.591  1.0
  O  O8  1  0.677  0.805  0.984  1.0
  O  O9  1  0.323  0.307  0.128  1.0
  O  O10  1  0.807  0.716  0.434  1.0
  O  O11  1  0.655  0.151  0.412  1.0
  O  O12  1  0.806  0.398  0.060  1.0
[/CIF]
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