The material structure described by Co9Se8 crystallizes in the cubic Fm-3m space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to six equivalent Se(2) atoms to form corner-sharing CoSe6 octahedra. In the second Co site, Co(2) is bonded to one Se(1) and three equivalent Se(2) atoms to form distorted CoSe4 tetrahedra that share corners with three equivalent Co(1)Se6 octahedra, corners with six equivalent Co(2)Se4 tetrahedra, and edges with three equivalent Co(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a tetrahedral geometry to four equivalent Co(2) atoms. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to one Co(1) and four equivalent Co(2) atoms. is represented by the CIF card [CIF]
data_Co9Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.233
_cell_length_b   7.233
_cell_length_c   7.233
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   267.564
_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
  Co  Co0  1  0.500  0.500  0.500  1.0
  Co  Co1  1  0.123  0.123  0.123  1.0
  Co  Co2  1  0.877  0.877  0.370  1.0
  Co  Co3  1  0.370  0.877  0.877  1.0
  Co  Co4  1  0.877  0.370  0.877  1.0
  Co  Co5  1  0.630  0.123  0.123  1.0
  Co  Co6  1  0.123  0.630  0.123  1.0
  Co  Co7  1  0.123  0.123  0.630  1.0
  Co  Co8  1  0.877  0.877  0.877  1.0
  Se  Se9  1  0.250  0.250  0.250  1.0
  Se  Se10  1  0.750  0.750  0.750  1.0
  Se  Se11  1  0.736  0.264  0.264  1.0
  Se  Se12  1  0.736  0.736  0.264  1.0
  Se  Se13  1  0.264  0.264  0.736  1.0
  Se  Se14  1  0.736  0.264  0.736  1.0
  Se  Se15  1  0.264  0.736  0.264  1.0
  Se  Se16  1  0.264  0.736  0.736  1.0
[/CIF]
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The material structure described by Co9Se8 crystallizes in the cubic Fm-3m space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to six equivalent Se(2) atoms to form corner-sharing CoSe6 octahedra. In the second Co site, Co(2) is bonded to one Se(1) and three equivalent Se(2) atoms to form distorted CoSe4 tetrahedra that share corners with three equivalent Co(1)Se6 octahedra, corners with six equivalent Co(2)Se4 tetrahedra, and edges with three equivalent Co(2)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a tetrahedral geometry to four equivalent Co(2) atoms. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to one Co(1) and four equivalent Co(2) atoms. is represented by the CIF card [CIF]
data_Co9Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.233
_cell_length_b   7.233
_cell_length_c   7.233
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   267.564
_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
  Co  Co0  1  0.500  0.500  0.500  1.0
  Co  Co1  1  0.123  0.123  0.123  1.0
  Co  Co2  1  0.877  0.877  0.370  1.0
  Co  Co3  1  0.370  0.877  0.877  1.0
  Co  Co4  1  0.877  0.370  0.877  1.0
  Co  Co5  1  0.630  0.123  0.123  1.0
  Co  Co6  1  0.123  0.630  0.123  1.0
  Co  Co7  1  0.123  0.123  0.630  1.0
  Co  Co8  1  0.877  0.877  0.877  1.0
  Se  Se9  1  0.250  0.250  0.250  1.0
  Se  Se10  1  0.750  0.750  0.750  1.0
  Se  Se11  1  0.736  0.264  0.264  1.0
  Se  Se12  1  0.736  0.736  0.264  1.0
  Se  Se13  1  0.264  0.264  0.736  1.0
  Se  Se14  1  0.736  0.264  0.736  1.0
  Se  Se15  1  0.264  0.736  0.264  1.0
  Se  Se16  1  0.264  0.736  0.736  1.0
[/CIF]
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