The crystal structure described by MgCr2Al4O10 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form distorted MgO6 octahedra that share corners with two equivalent Al(1)O5 trigonal bipyramids, corners with four equivalent Cr(1)O5 trigonal bipyramids, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Al(1)O5 trigonal bipyramids. Cr(1) is bonded to one O(1), one O(3), one O(4), and two equivalent O(5) atoms to form distorted CrO5 trigonal bipyramids that share  a cornercorner with one Al(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Cr(1)O5 trigonal bipyramids, corners with three equivalent Al(1)O5 trigonal bipyramids, and edges with three equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 22-66°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(3), one O(5), and three equivalent O(2) atoms to form distorted AlO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra, corners with two equivalent Al(1)O5 trigonal bipyramids, corners with three equivalent Cr(1)O5 trigonal bipyramids, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Al(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-77°. In the second Al site, Al(2) is bonded to one O(5), two equivalent O(1), and three equivalent O(4) atoms to form distorted AlO6 octahedra that share corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Cr(1)O5 trigonal bipyramid,  a cornercorner with one Al(1)O5 trigonal bipyramid, edges with three equivalent Al(2)O6 octahedra, and edges with three equivalent Cr(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 34°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Cr(1) and two equivalent Al(2) atoms. In the second O site, O(2) is bonded to one Mg(1) and three equivalent Al(1) atoms to form distorted OMgAl3 trigonal pyramids that share corners with three equivalent O(5)Al2Cr2 tetrahedra, corners with three equivalent O(3)Mg2AlCr trigonal pyramids, corners with three equivalent O(2)MgAl3 trigonal pyramids, edges with two equivalent O(3)Mg2AlCr trigonal pyramids, and edges with two equivalent O(2)MgAl3 trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Mg(1), one Cr(1), and one Al(1) atom to form distorted OMg2AlCr trigonal pyramids that share corners with three equivalent O(5)Al2Cr2 tetrahedra,  a cornercorner with one O(4)Al3Cr trigonal pyramid, corners with three equivalent O(2)MgAl3 trigonal pyramids, corners with four equivalent O(3)Mg2AlCr trigonal pyramids,  an edgeedge with one O(3)Mg2AlCr trigonal pyramid, and edges with two equivalent O(2)MgAl3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Cr(1) and three equivalent Al(2) atoms to form OAl3Cr trigonal pyramids that share  a cornercorner with one O(5)Al2Cr2 tetrahedra,  a cornercorner with one O(3)Mg2AlCr trigonal pyramid, corners with two equivalent O(4)Al3Cr trigonal pyramids, edges with two equivalent O(5)Al2Cr2 tetrahedra, and edges with two equivalent O(4)Al3Cr trigonal pyramids. In the fifth O site, O(5) is bonded to two equivalent Cr(1), one Al(1), and one Al(2) atom to form distorted OAl2Cr2 tetrahedra that share corners with two equivalent O(5)Al2Cr2 tetrahedra,  a cornercorner with one O(4)Al3Cr trigonal pyramid, corners with three equivalent O(3)Mg2AlCr trigonal pyramids, corners with three equivalent O(2)MgAl3 trigonal pyramids, and edges with two equivalent O(4)Al3Cr trigonal pyramids. is represented by the CIF file [CIF]
data_MgAl4Cr2O10
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.680
_cell_length_b   5.155
_cell_length_c   10.300
_cell_angle_alpha   83.342
_cell_angle_beta   90.001
_cell_angle_gamma   110.905
_symmetry_Int_Tables_number   1
_cell_volume   181.115
_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  0.000  0.500  1.0
  Al  Al1  1  0.180  0.359  0.602  1.0
  Al  Al2  1  0.143  0.286  0.952  1.0
  Al  Al3  1  0.857  0.714  0.048  1.0
  Al  Al4  1  0.820  0.641  0.398  1.0
  Cr  Cr5  1  0.156  0.312  0.233  1.0
  Cr  Cr6  1  0.844  0.688  0.767  1.0
  O  O7  1  0.027  0.054  0.110  1.0
  O  O8  1  0.305  0.610  0.437  1.0
  O  O9  1  0.008  0.016  0.380  1.0
  O  O10  1  0.299  0.598  0.067  1.0
  O  O11  1  0.272  0.544  0.746  1.0
  O  O12  1  0.728  0.456  0.254  1.0
  O  O13  1  0.701  0.402  0.933  1.0
  O  O14  1  0.695  0.390  0.563  1.0
  O  O15  1  0.992  0.984  0.620  1.0
  O  O16  1  0.973  0.946  0.890  1.0
[/CIF]
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The crystal structure described by MgCr2Al4O10 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form distorted MgO6 octahedra that share corners with two equivalent Al(1)O5 trigonal bipyramids, corners with four equivalent Cr(1)O5 trigonal bipyramids, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Al(1)O5 trigonal bipyramids. Cr(1) is bonded to one O(1), one O(3), one O(4), and two equivalent O(5) atoms to form distorted CrO5 trigonal bipyramids that share  a cornercorner with one Al(2)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Cr(1)O5 trigonal bipyramids, corners with three equivalent Al(1)O5 trigonal bipyramids, and edges with three equivalent Al(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 22-66°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(3), one O(5), and three equivalent O(2) atoms to form distorted AlO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Al(2)O6 octahedra, corners with two equivalent Al(1)O5 trigonal bipyramids, corners with three equivalent Cr(1)O5 trigonal bipyramids, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Al(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 61-77°. In the second Al site, Al(2) is bonded to one O(5), two equivalent O(1), and three equivalent O(4) atoms to form distorted AlO6 octahedra that share corners with two equivalent Al(2)O6 octahedra,  a cornercorner with one Cr(1)O5 trigonal bipyramid,  a cornercorner with one Al(1)O5 trigonal bipyramid, edges with three equivalent Al(2)O6 octahedra, and edges with three equivalent Cr(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 34°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Cr(1) and two equivalent Al(2) atoms. In the second O site, O(2) is bonded to one Mg(1) and three equivalent Al(1) atoms to form distorted OMgAl3 trigonal pyramids that share corners with three equivalent O(5)Al2Cr2 tetrahedra, corners with three equivalent O(3)Mg2AlCr trigonal pyramids, corners with three equivalent O(2)MgAl3 trigonal pyramids, edges with two equivalent O(3)Mg2AlCr trigonal pyramids, and edges with two equivalent O(2)MgAl3 trigonal pyramids. In the third O site, O(3) is bonded to two equivalent Mg(1), one Cr(1), and one Al(1) atom to form distorted OMg2AlCr trigonal pyramids that share corners with three equivalent O(5)Al2Cr2 tetrahedra,  a cornercorner with one O(4)Al3Cr trigonal pyramid, corners with three equivalent O(2)MgAl3 trigonal pyramids, corners with four equivalent O(3)Mg2AlCr trigonal pyramids,  an edgeedge with one O(3)Mg2AlCr trigonal pyramid, and edges with two equivalent O(2)MgAl3 trigonal pyramids. In the fourth O site, O(4) is bonded to one Cr(1) and three equivalent Al(2) atoms to form OAl3Cr trigonal pyramids that share  a cornercorner with one O(5)Al2Cr2 tetrahedra,  a cornercorner with one O(3)Mg2AlCr trigonal pyramid, corners with two equivalent O(4)Al3Cr trigonal pyramids, edges with two equivalent O(5)Al2Cr2 tetrahedra, and edges with two equivalent O(4)Al3Cr trigonal pyramids. In the fifth O site, O(5) is bonded to two equivalent Cr(1), one Al(1), and one Al(2) atom to form distorted OAl2Cr2 tetrahedra that share corners with two equivalent O(5)Al2Cr2 tetrahedra,  a cornercorner with one O(4)Al3Cr trigonal pyramid, corners with three equivalent O(3)Mg2AlCr trigonal pyramids, corners with three equivalent O(2)MgAl3 trigonal pyramids, and edges with two equivalent O(4)Al3Cr trigonal pyramids. is represented by the CIF file [CIF]
data_MgAl4Cr2O10
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.680
_cell_length_b   5.155
_cell_length_c   10.300
_cell_angle_alpha   83.342
_cell_angle_beta   90.001
_cell_angle_gamma   110.905
_symmetry_Int_Tables_number   1
_cell_volume   181.115
_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  0.000  0.500  1.0
  Al  Al1  1  0.180  0.359  0.602  1.0
  Al  Al2  1  0.143  0.286  0.952  1.0
  Al  Al3  1  0.857  0.714  0.048  1.0
  Al  Al4  1  0.820  0.641  0.398  1.0
  Cr  Cr5  1  0.156  0.312  0.233  1.0
  Cr  Cr6  1  0.844  0.688  0.767  1.0
  O  O7  1  0.027  0.054  0.110  1.0
  O  O8  1  0.305  0.610  0.437  1.0
  O  O9  1  0.008  0.016  0.380  1.0
  O  O10  1  0.299  0.598  0.067  1.0
  O  O11  1  0.272  0.544  0.746  1.0
  O  O12  1  0.728  0.456  0.254  1.0
  O  O13  1  0.701  0.402  0.933  1.0
  O  O14  1  0.695  0.390  0.563  1.0
  O  O15  1  0.992  0.984  0.620  1.0
  O  O16  1  0.973  0.946  0.890  1.0
[/CIF]
.