The material structure described by MgAlCrO4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted MgO4 tetrahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, and  an edgeedge with one Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-62°. Cr(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. Al(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with four equivalent Mg(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Cr(1), and one Al(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Al(1) atoms. 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 in a trigonal planar geometry to one Cr(1) and two equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_MgAlCrO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.107
_cell_length_b   5.957
_cell_length_c   5.176
_cell_angle_alpha   103.525
_cell_angle_beta   74.809
_cell_angle_gamma   150.485
_symmetry_Int_Tables_number   1
_cell_volume   74.862
_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  0.802  0.012  0.801  1.0
  Al  Al1  1  0.461  0.989  0.469  1.0
  Cr  Cr2  1  0.612  0.520  0.081  1.0
  O  O3  1  0.188  0.996  0.801  1.0
  O  O4  1  0.143  0.501  0.643  1.0
  O  O5  1  0.813  0.003  0.193  1.0
  O  O6  1  0.798  0.475  0.321  1.0
[/CIF]
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The material structure described by MgAlCrO4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form distorted MgO4 tetrahedra that share corners with four equivalent Al(1)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, and  an edgeedge with one Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-62°. Cr(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. Al(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form AlO6 octahedra that share corners with four equivalent Mg(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Cr(1), and one Al(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Al(1) atoms. 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 in a trigonal planar geometry to one Cr(1) and two equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_MgAlCrO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.107
_cell_length_b   5.957
_cell_length_c   5.176
_cell_angle_alpha   103.525
_cell_angle_beta   74.809
_cell_angle_gamma   150.485
_symmetry_Int_Tables_number   1
_cell_volume   74.862
_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  0.802  0.012  0.801  1.0
  Al  Al1  1  0.461  0.989  0.469  1.0
  Cr  Cr2  1  0.612  0.520  0.081  1.0
  O  O3  1  0.188  0.996  0.801  1.0
  O  O4  1  0.143  0.501  0.643  1.0
  O  O5  1  0.813  0.003  0.193  1.0
  O  O6  1  0.798  0.475  0.321  1.0
[/CIF]
.