The structure described by Cr4CuAlSe8 is Spinel-derived structured and crystallizes in the cubic F-43m space group. Cr(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form CrSe6 octahedra that share corners with three equivalent Cu(1)Se4 tetrahedra, corners with three equivalent Al(1)Se4 tetrahedra, and edges with six equivalent Cr(1)Se6 octahedra. Cu(1) is bonded to four equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with twelve equivalent Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 56°. Al(1) is bonded to four equivalent Se(2) atoms to form AlSe4 tetrahedra that share corners with twelve equivalent Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(1) and one Cu(1) atom. In the second Se site, Se(2) is bonded to three equivalent Cr(1) and one Al(1) atom to form a mixture of distorted corner and edge-sharing SeAlCr3 trigonal pyramids. is represented by the CIF card [CIF]
data_AlCr4CuSe8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.415
_cell_length_b   7.415
_cell_length_c   7.415
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   288.287
_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
  Al  Al0  1  0.500  0.500  0.500  1.0
  Cr  Cr1  1  0.637  0.121  0.121  1.0
  Cr  Cr2  1  0.121  0.637  0.121  1.0
  Cr  Cr3  1  0.121  0.121  0.637  1.0
  Cr  Cr4  1  0.121  0.121  0.121  1.0
  Cu  Cu5  1  0.750  0.750  0.750  1.0
  Se  Se6  1  0.351  0.883  0.883  1.0
  Se  Se7  1  0.883  0.351  0.883  1.0
  Se  Se8  1  0.883  0.883  0.351  1.0
  Se  Se9  1  0.883  0.883  0.883  1.0
  Se  Se10  1  0.898  0.367  0.367  1.0
  Se  Se11  1  0.367  0.898  0.367  1.0
  Se  Se12  1  0.367  0.367  0.898  1.0
  Se  Se13  1  0.367  0.367  0.367  1.0
[/CIF]
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The structure described by Cr4CuAlSe8 is Spinel-derived structured and crystallizes in the cubic F-43m space group. Cr(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form CrSe6 octahedra that share corners with three equivalent Cu(1)Se4 tetrahedra, corners with three equivalent Al(1)Se4 tetrahedra, and edges with six equivalent Cr(1)Se6 octahedra. Cu(1) is bonded to four equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with twelve equivalent Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 56°. Al(1) is bonded to four equivalent Se(2) atoms to form AlSe4 tetrahedra that share corners with twelve equivalent Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a rectangular see-saw-like geometry to three equivalent Cr(1) and one Cu(1) atom. In the second Se site, Se(2) is bonded to three equivalent Cr(1) and one Al(1) atom to form a mixture of distorted corner and edge-sharing SeAlCr3 trigonal pyramids. is represented by the CIF card [CIF]
data_AlCr4CuSe8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.415
_cell_length_b   7.415
_cell_length_c   7.415
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   288.287
_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
  Al  Al0  1  0.500  0.500  0.500  1.0
  Cr  Cr1  1  0.637  0.121  0.121  1.0
  Cr  Cr2  1  0.121  0.637  0.121  1.0
  Cr  Cr3  1  0.121  0.121  0.637  1.0
  Cr  Cr4  1  0.121  0.121  0.121  1.0
  Cu  Cu5  1  0.750  0.750  0.750  1.0
  Se  Se6  1  0.351  0.883  0.883  1.0
  Se  Se7  1  0.883  0.351  0.883  1.0
  Se  Se8  1  0.883  0.883  0.351  1.0
  Se  Se9  1  0.883  0.883  0.883  1.0
  Se  Se10  1  0.898  0.367  0.367  1.0
  Se  Se11  1  0.367  0.898  0.367  1.0
  Se  Se12  1  0.367  0.367  0.898  1.0
  Se  Se13  1  0.367  0.367  0.367  1.0
[/CIF]
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