The material described by MgAl2O4 crystallizes in the orthorhombic Cmcm space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Al(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 0-51°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1) and three equivalent Al(1) atoms to form distorted OMg2Al3 trigonal bipyramids that share corners with four equivalent O(3)Mg2Al4 octahedra, corners with five equivalent O(2)Mg2Al2 tetrahedra, corners with two equivalent O(1)Mg2Al3 trigonal bipyramids, edges with three equivalent O(3)Mg2Al4 octahedra,  an edgeedge with one O(2)Mg2Al2 tetrahedra, and edges with five equivalent O(1)Mg2Al3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 10-42°. In the second O site, O(2) is bonded to two equivalent Mg(1) and two equivalent Al(1) atoms to form distorted OMg2Al2 tetrahedra that share corners with two equivalent O(2)Mg2Al2 tetrahedra, corners with ten equivalent O(1)Mg2Al3 trigonal bipyramids, edges with four equivalent O(3)Mg2Al4 octahedra, and edges with two equivalent O(1)Mg2Al3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Mg(1) and four equivalent Al(1) atoms to form distorted OMg2Al4 octahedra that share corners with two equivalent O(3)Mg2Al4 octahedra, corners with eight equivalent O(1)Mg2Al3 trigonal bipyramids, edges with two equivalent O(3)Mg2Al4 octahedra, edges with four equivalent O(2)Mg2Al2 tetrahedra, and edges with six equivalent O(1)Mg2Al3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 47°. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgAl2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.844
_cell_length_b   4.844
_cell_length_c   9.462
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   146.321
_symmetry_Int_Tables_number   1
_cell_volume   123.109
_cell_formula_units_Z   2
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  0.389  0.611  0.250  1.0
  Mg  Mg1  1  0.611  0.389  0.750  1.0
  Al  Al2  1  0.865  0.135  0.927  1.0
  Al  Al3  1  0.135  0.865  0.427  1.0
  Al  Al4  1  0.135  0.865  0.073  1.0
  Al  Al5  1  0.865  0.135  0.573  1.0
  O  O6  1  0.230  0.770  0.890  1.0
  O  O7  1  0.230  0.770  0.610  1.0
  O  O8  1  0.770  0.230  0.390  1.0
  O  O9  1  0.952  0.048  0.750  1.0
  O  O10  1  0.770  0.230  0.110  1.0
  O  O11  1  0.500  0.500  0.500  1.0
  O  O12  1  0.500  0.500  0.000  1.0
  O  O13  1  0.048  0.952  0.250  1.0
[/CIF]
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The material described by MgAl2O4 crystallizes in the orthorhombic Cmcm space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Al(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles range from 0-51°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1) and three equivalent Al(1) atoms to form distorted OMg2Al3 trigonal bipyramids that share corners with four equivalent O(3)Mg2Al4 octahedra, corners with five equivalent O(2)Mg2Al2 tetrahedra, corners with two equivalent O(1)Mg2Al3 trigonal bipyramids, edges with three equivalent O(3)Mg2Al4 octahedra,  an edgeedge with one O(2)Mg2Al2 tetrahedra, and edges with five equivalent O(1)Mg2Al3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 10-42°. In the second O site, O(2) is bonded to two equivalent Mg(1) and two equivalent Al(1) atoms to form distorted OMg2Al2 tetrahedra that share corners with two equivalent O(2)Mg2Al2 tetrahedra, corners with ten equivalent O(1)Mg2Al3 trigonal bipyramids, edges with four equivalent O(3)Mg2Al4 octahedra, and edges with two equivalent O(1)Mg2Al3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Mg(1) and four equivalent Al(1) atoms to form distorted OMg2Al4 octahedra that share corners with two equivalent O(3)Mg2Al4 octahedra, corners with eight equivalent O(1)Mg2Al3 trigonal bipyramids, edges with two equivalent O(3)Mg2Al4 octahedra, edges with four equivalent O(2)Mg2Al2 tetrahedra, and edges with six equivalent O(1)Mg2Al3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 47°. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgAl2O4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.844
_cell_length_b   4.844
_cell_length_c   9.462
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   146.321
_symmetry_Int_Tables_number   1
_cell_volume   123.109
_cell_formula_units_Z   2
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  0.389  0.611  0.250  1.0
  Mg  Mg1  1  0.611  0.389  0.750  1.0
  Al  Al2  1  0.865  0.135  0.927  1.0
  Al  Al3  1  0.135  0.865  0.427  1.0
  Al  Al4  1  0.135  0.865  0.073  1.0
  Al  Al5  1  0.865  0.135  0.573  1.0
  O  O6  1  0.230  0.770  0.890  1.0
  O  O7  1  0.230  0.770  0.610  1.0
  O  O8  1  0.770  0.230  0.390  1.0
  O  O9  1  0.952  0.048  0.750  1.0
  O  O10  1  0.770  0.230  0.110  1.0
  O  O11  1  0.500  0.500  0.500  1.0
  O  O12  1  0.500  0.500  0.000  1.0
  O  O13  1  0.048  0.952  0.250  1.0
[/CIF]
.