data_Co9Se8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.31
_cell_length_b   7.31
_cell_length_c   7.31
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Co9Se8
_chemical_formula_sum   'Co9 Se8'
_cell_volume   276.49
_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  0.0  0.0  0.0  1.0
  Co  Co1  1  0.45  0.45  0.45  1.0
  Co  Co2  1  0.45  0.45  0.89  1.0
  Co  Co3  1  0.89  0.45  0.45  1.0
  Co  Co4  1  0.45  0.89  0.45  1.0
  Co  Co5  1  0.45  0.89  0.89  1.0
  Co  Co6  1  0.89  0.45  0.89  1.0
  Co  Co7  1  0.89  0.89  0.45  1.0
  Co  Co8  1  0.89  0.89  0.89  1.0
  Se  Se9  1  0.76  0.76  0.76  1.0
  Se  Se10  1  0.59  0.59  0.59  1.0
  Se  Se11  1  0.9  0.17  0.17  1.0
  Se  Se12  1  0.17  0.17  0.44  1.0
  Se  Se13  1  0.17  0.17  0.9  1.0
  Se  Se14  1  0.17  0.44  0.17  1.0
  Se  Se15  1  0.17  0.9  0.17  1.0
  Se  Se16  1  0.44  0.17  0.17  1.0

data_Co9Se8
_symmetry_space_group_name_H-M   R3m
_cell_length_a   7.31
_cell_length_b   7.31
_cell_length_c   17.91
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Co9Se8
_chemical_formula_sum   'Co27 Se24'
_cell_volume   829.48
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  9  0.03  0.52  0.07  1.0
  Co  Co1  9  0.18  0.37  0.92  1.0
  Co  Co2  3  0.0  0.0  0.0  1.0
  Co  Co3  3  0.0  0.0  0.11  1.0
  Co  Co4  3  0.0  0.0  0.55  1.0
  Se  Se5  9  0.09  0.18  0.74  1.0
  Se  Se6  9  0.18  0.09  0.92  1.0
  Se  Se7  3  0.0  0.0  0.24  1.0
  Se  Se8  3  0.0  0.0  0.41  1.0

Co Co Co Co Co Co Co Co Co Se Se Se Se Se Se Se Se
Co Co Co Co Co Co Co Co Co Se Se Se Se Se Se Se Se 0 8 - - - 0 11 - o o 0 15 o - o 0 13 o o - 1 16 o o o 1 14 o o o 1 12 o o o 1 13 o o o 1 15 o o o 1 11 o o o 1 10 o o o 1 4 o o o 1 3 o o o 1 2 o o o 2 16 o o + 2 14 o o + 2 10 o o o 3 10 o o o 3 14 + o o 3 12 + o o 4 12 o + o 4 10 o o o 4 16 o + o 5 13 o + o 5 15 o o + 5 9 o o o 6 11 o o + 6 9 o o o 6 13 + o o 7 9 o o o 7 15 + o o 7 11 o + o 11 15 + - o 11 13 + o - 12 16 o o o 12 14 o o o 13 15 o - + 14 16 o o o 
Co9Se8 crystallizes in the trigonal R3m space group. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded in a 4-coordinate geometry to one Co(5) and three equivalent Se(3) atoms. The Co(1)-Co(5) bond length is 1.89 Å. All Co(1)-Se(3) bond lengths are 1.84 Å. In the second Co site, Co(2) is bonded in a 4-coordinate geometry to one Se(2) and three equivalent Se(3) atoms. The Co(2)-Se(2) bond length is 2.48 Å. All Co(2)-Se(3) bond lengths are 3.13 Å. In the third Co site, Co(3) is bonded in a 3-coordinate geometry to one Se(2) and two equivalent Se(4) atoms. The Co(3)-Se(2) bond length is 1.90 Å. Both Co(3)-Se(4) bond lengths are 2.02 Å. In the fourth Co site, Co(4) is bonded in a 3-coordinate geometry to one Se(1) and two equivalent Se(3) atoms. The Co(4)-Se(1) bond length is 1.90 Å. Both Co(4)-Se(3) bond lengths are 2.02 Å. In the fifth Co site, Co(5) is bonded in a 5-coordinate geometry to one Co(1), one Se(1), and three equivalent Se(4) atoms. The Co(5)-Se(1) bond length is 2.48 Å. All Co(5)-Se(4) bond lengths are 3.13 Å. There are four inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted trigonal pyramidal geometry to one Co(5) and three equivalent Co(4) atoms. In the second Se site, Se(2) is bonded in a distorted trigonal pyramidal geometry to one Co(2) and three equivalent Co(3) atoms. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Co(1), one Co(2), and two equivalent Co(4) atoms. In the fourth Se site, Se(4) is bonded in a distorted linear geometry to one Co(5) and two equivalent Co(3) atoms.