data_CdBiSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.16
_cell_length_b   5.16
_cell_length_c   5.16
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CdBiSe2
_chemical_formula_sum   'Cd1 Bi1 Se2'
_cell_volume   96.94
_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
  Cd  Cd1  1  0.0  0.0  0.0  1.0
  Bi  Bi0  1  0.65  0.65  0.65  1.0
  Se  Se2  1  0.47  0.47  0.47  1.0
  Se  Se3  1  0.82  0.82  0.82  1.0

data_CdBiSe2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.16
_cell_length_b   5.16
_cell_length_c   12.63
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CdBiSe2
_chemical_formula_sum   'Cd3 Bi3 Se6'
_cell_volume   290.81
_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
  Cd  Cd0  3  0.0  0.0  0.0  1.0
  Bi  Bi1  3  0.0  0.0  0.35  1.0
  Se  Se2  3  0.0  0.0  0.18  1.0
  Se  Se3  3  0.0  0.0  0.53  1.0

Cd Bi Se Se
CdBiSe2 crystallizes in the trigonal R3m space group. Cd(1) is bonded in a distorted single-bond geometry to three equivalent Bi(1) and one Se(2) atom. All Cd(1)-Bi(1) bond lengths are 2.99 Å. The Cd(1)-Se(2) bond length is 2.24 Å. Bi(1) is bonded in a distorted linear geometry to three equivalent Cd(1), one Se(1), and one Se(2) atom. The Bi(1)-Se(1) bond length is 2.24 Å. The Bi(1)-Se(2) bond length is 2.24 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a single-bond geometry to one Bi(1) atom. In the second Se site, Se(2) is bonded in a linear geometry to one Cd(1) and one Bi(1) atom.