The structure described by GaAl(CuSe2)2 is Stannite-like structured and crystallizes in the tetragonal I-4 space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to four equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with four equivalent Cu(2)Se4 tetrahedra, corners with four equivalent Ga(1)Se4 tetrahedra, and corners with four equivalent Al(1)Se4 tetrahedra. In the second Cu site, Cu(2) is bonded to four equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Ga(1)Se4 tetrahedra, and corners with four equivalent Al(1)Se4 tetrahedra. Ga(1) is bonded to four equivalent Se(1) atoms to form GaSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and corners with four equivalent Al(1)Se4 tetrahedra. Al(1) is bonded to four equivalent Se(1) atoms to form AlSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and corners with four equivalent Ga(1)Se4 tetrahedra. Se(1) is bonded to one Cu(1), one Cu(2), one Ga(1), and one Al(1) atom to form corner-sharing SeAlGaCu2 tetrahedra. is represented by the CIF card [CIF]
data_AlGa(CuSe2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.868
_cell_length_b   6.868
_cell_length_c   6.868
_cell_angle_alpha   131.388
_cell_angle_beta   131.388
_cell_angle_gamma   71.198
_symmetry_Int_Tables_number   1
_cell_volume   178.534
_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  0.000  1.0
  Ga  Ga1  1  0.750  0.250  0.500  1.0
  Cu  Cu2  1  0.250  0.750  0.500  1.0
  Cu  Cu3  1  0.000  0.000  0.000  1.0
  Se  Se4  1  0.624  0.629  0.500  1.0
  Se  Se5  1  0.129  0.124  0.500  1.0
  Se  Se6  1  0.876  0.376  0.005  1.0
  Se  Se7  1  0.371  0.871  0.995  1.0
[/CIF]
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The structure described by GaAl(CuSe2)2 is Stannite-like structured and crystallizes in the tetragonal I-4 space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to four equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with four equivalent Cu(2)Se4 tetrahedra, corners with four equivalent Ga(1)Se4 tetrahedra, and corners with four equivalent Al(1)Se4 tetrahedra. In the second Cu site, Cu(2) is bonded to four equivalent Se(1) atoms to form CuSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Ga(1)Se4 tetrahedra, and corners with four equivalent Al(1)Se4 tetrahedra. Ga(1) is bonded to four equivalent Se(1) atoms to form GaSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and corners with four equivalent Al(1)Se4 tetrahedra. Al(1) is bonded to four equivalent Se(1) atoms to form AlSe4 tetrahedra that share corners with four equivalent Cu(1)Se4 tetrahedra, corners with four equivalent Cu(2)Se4 tetrahedra, and corners with four equivalent Ga(1)Se4 tetrahedra. Se(1) is bonded to one Cu(1), one Cu(2), one Ga(1), and one Al(1) atom to form corner-sharing SeAlGaCu2 tetrahedra. is represented by the CIF card [CIF]
data_AlGa(CuSe2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.868
_cell_length_b   6.868
_cell_length_c   6.868
_cell_angle_alpha   131.388
_cell_angle_beta   131.388
_cell_angle_gamma   71.198
_symmetry_Int_Tables_number   1
_cell_volume   178.534
_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  0.000  1.0
  Ga  Ga1  1  0.750  0.250  0.500  1.0
  Cu  Cu2  1  0.250  0.750  0.500  1.0
  Cu  Cu3  1  0.000  0.000  0.000  1.0
  Se  Se4  1  0.624  0.629  0.500  1.0
  Se  Se5  1  0.129  0.124  0.500  1.0
  Se  Se6  1  0.876  0.376  0.005  1.0
  Se  Se7  1  0.371  0.871  0.995  1.0
[/CIF]
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