The compound described by MgAl4(CuO4)2 crystallizes in the trigonal R-3m space group. Mg(1) is bonded to six equivalent O(1) atoms to form distorted MgO6 octahedra that share corners with six equivalent Al(2)O6 octahedra and edges with six equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 10°. Cu(1) is bonded in a 4-coordinate geometry to one O(2) and three equivalent O(1) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form AlO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Al(2)O6 octahedra, and edges with four equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to six equivalent O(1) atoms to form AlO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra and edges with six equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Cu(1), one Al(2), and two equivalent Al(1) atoms to form distorted OMgAl3Cu square pyramids that share corners with six equivalent O(1)MgAl3Cu square pyramids, corners with three equivalent O(2)Al3Cu tetrahedra, edges with six equivalent O(1)MgAl3Cu square pyramids, and  an edgeedge with one O(2)Al3Cu tetrahedra. In the second O site, O(2) is bonded to one Cu(1) and three equivalent Al(1) atoms to form OAl3Cu tetrahedra that share corners with nine equivalent O(1)MgAl3Cu square pyramids, corners with three equivalent O(2)Al3Cu tetrahedra, and edges with three equivalent O(1)MgAl3Cu square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgAl4(CuO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.749
_cell_length_b   5.749
_cell_length_c   6.059
_cell_angle_alpha   61.679
_cell_angle_beta   61.679
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   145.101
_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  0.000  0.000  0.500  1.0
  Al  Al1  1  0.500  0.000  0.500  1.0
  Al  Al2  1  0.000  0.500  0.500  1.0
  Al  Al3  1  0.500  0.500  0.000  1.0
  Al  Al4  1  0.500  0.500  0.500  1.0
  Cu  Cu5  1  0.156  0.156  0.031  1.0
  Cu  Cu6  1  0.844  0.844  0.969  1.0
  O  O7  1  0.744  0.744  0.726  1.0
  O  O8  1  0.278  0.278  0.666  1.0
  O  O9  1  0.256  0.713  0.274  1.0
  O  O10  1  0.713  0.256  0.274  1.0
  O  O11  1  0.744  0.287  0.726  1.0
  O  O12  1  0.287  0.744  0.726  1.0
  O  O13  1  0.256  0.256  0.274  1.0
  O  O14  1  0.722  0.722  0.334  1.0
[/CIF]
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The compound described by MgAl4(CuO4)2 crystallizes in the trigonal R-3m space group. Mg(1) is bonded to six equivalent O(1) atoms to form distorted MgO6 octahedra that share corners with six equivalent Al(2)O6 octahedra and edges with six equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 10°. Cu(1) is bonded in a 4-coordinate geometry to one O(2) and three equivalent O(1) atoms. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form AlO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Al(2)O6 octahedra, and edges with four equivalent Al(1)O6 octahedra. In the second Al site, Al(2) is bonded to six equivalent O(1) atoms to form AlO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra and edges with six equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Cu(1), one Al(2), and two equivalent Al(1) atoms to form distorted OMgAl3Cu square pyramids that share corners with six equivalent O(1)MgAl3Cu square pyramids, corners with three equivalent O(2)Al3Cu tetrahedra, edges with six equivalent O(1)MgAl3Cu square pyramids, and  an edgeedge with one O(2)Al3Cu tetrahedra. In the second O site, O(2) is bonded to one Cu(1) and three equivalent Al(1) atoms to form OAl3Cu tetrahedra that share corners with nine equivalent O(1)MgAl3Cu square pyramids, corners with three equivalent O(2)Al3Cu tetrahedra, and edges with three equivalent O(1)MgAl3Cu square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgAl4(CuO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.749
_cell_length_b   5.749
_cell_length_c   6.059
_cell_angle_alpha   61.679
_cell_angle_beta   61.679
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   145.101
_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  0.000  0.000  0.500  1.0
  Al  Al1  1  0.500  0.000  0.500  1.0
  Al  Al2  1  0.000  0.500  0.500  1.0
  Al  Al3  1  0.500  0.500  0.000  1.0
  Al  Al4  1  0.500  0.500  0.500  1.0
  Cu  Cu5  1  0.156  0.156  0.031  1.0
  Cu  Cu6  1  0.844  0.844  0.969  1.0
  O  O7  1  0.744  0.744  0.726  1.0
  O  O8  1  0.278  0.278  0.666  1.0
  O  O9  1  0.256  0.713  0.274  1.0
  O  O10  1  0.713  0.256  0.274  1.0
  O  O11  1  0.744  0.287  0.726  1.0
  O  O12  1  0.287  0.744  0.726  1.0
  O  O13  1  0.256  0.256  0.274  1.0
  O  O14  1  0.722  0.722  0.334  1.0
[/CIF]
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