data_TlBiSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.03
_cell_length_b   8.03
_cell_length_c   8.03
_cell_angle_alpha   31.16
_cell_angle_beta   31.16
_cell_angle_gamma   31.16
_symmetry_Int_Tables_number   1
_chemical_formula_structural   TlBiSe2
_chemical_formula_sum   'Tl1 Bi1 Se2'
_cell_volume   123.11
_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
  Tl  Tl0  1  0.0  0.0  0.0  1.0
  Bi  Bi1  1  0.0  0.0  0.45  1.0
  Se  Se2  1  0.0  0.0  0.47  1.0
  Se  Se3  1  0.0  0.0  0.44  1.0

data_TlBiSe2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   7.47
_cell_length_b   4.31
_cell_length_c   8.03
_cell_angle_alpha   90.0
_cell_angle_beta   108.07
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   TlBiSe2
_chemical_formula_sum   'Tl2 Bi2 Se4'
_cell_volume   246.22
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Tl  Tl0  2  0.0  0.0  0.0  1.0
  Bi  Bi1  2  0.0  0.0  0.55  1.0
  Se  Se2  2  0.0  0.0  0.53  1.0
  Se  Se3  2  0.0  0.0  0.56  1.0

Tl Bi Se Se
TlBiSe2 is Cyanogen Chloride-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two 7440-28-0 atoms and two BiSe2 clusters. In each BiSe2 cluster, Bi(1) is bonded in a linear geometry to one Se(1) and one Se(2) atom. The Bi(1)-Se(1) bond length is 0.14 Å. The Bi(1)-Se(2) bond length is 0.14 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 single-bond geometry to one Bi(1) atom.