The crystal structure described by Al5Se8 is beta indium sulfide-like structured and crystallizes in the cubic F-43m space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form AlSe6 octahedra that share corners with three equivalent Al(2)Se4 tetrahedra and edges with six equivalent Al(1)Se6 octahedra. In the second Al site, Al(2) is bonded to four equivalent Se(2) atoms to form corner-sharing AlSe4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded to one Al(2) and three equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing SeAl4 tetrahedra. In the second Se site, Se(1) is bonded in a distorted T-shaped geometry to three equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_Al5Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.447
_cell_length_b   7.447
_cell_length_c   7.447
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   292.043
_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  0.885  0.885  0.345  1.0
  Al  Al1  1  0.885  0.345  0.885  1.0
  Al  Al2  1  0.345  0.885  0.885  1.0
  Al  Al3  1  0.885  0.885  0.885  1.0
  Al  Al4  1  0.500  0.500  0.500  1.0
  Se  Se5  1  0.123  0.123  0.631  1.0
  Se  Se6  1  0.123  0.631  0.123  1.0
  Se  Se7  1  0.631  0.123  0.123  1.0
  Se  Se8  1  0.123  0.123  0.123  1.0
  Se  Se9  1  0.634  0.634  0.098  1.0
  Se  Se10  1  0.634  0.098  0.634  1.0
  Se  Se11  1  0.098  0.634  0.634  1.0
  Se  Se12  1  0.634  0.634  0.634  1.0
[/CIF]
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The crystal structure described by Al5Se8 is beta indium sulfide-like structured and crystallizes in the cubic F-43m space group. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to three equivalent Se(1) and three equivalent Se(2) atoms to form AlSe6 octahedra that share corners with three equivalent Al(2)Se4 tetrahedra and edges with six equivalent Al(1)Se6 octahedra. In the second Al site, Al(2) is bonded to four equivalent Se(2) atoms to form corner-sharing AlSe4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. There are two inequivalent Se sites. In the first Se site, Se(2) is bonded to one Al(2) and three equivalent Al(1) atoms to form a mixture of distorted edge and corner-sharing SeAl4 tetrahedra. In the second Se site, Se(1) is bonded in a distorted T-shaped geometry to three equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_Al5Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.447
_cell_length_b   7.447
_cell_length_c   7.447
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   292.043
_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  0.885  0.885  0.345  1.0
  Al  Al1  1  0.885  0.345  0.885  1.0
  Al  Al2  1  0.345  0.885  0.885  1.0
  Al  Al3  1  0.885  0.885  0.885  1.0
  Al  Al4  1  0.500  0.500  0.500  1.0
  Se  Se5  1  0.123  0.123  0.631  1.0
  Se  Se6  1  0.123  0.631  0.123  1.0
  Se  Se7  1  0.631  0.123  0.123  1.0
  Se  Se8  1  0.123  0.123  0.123  1.0
  Se  Se9  1  0.634  0.634  0.098  1.0
  Se  Se10  1  0.634  0.098  0.634  1.0
  Se  Se11  1  0.098  0.634  0.634  1.0
  Se  Se12  1  0.634  0.634  0.634  1.0
[/CIF]
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