data_Tl3As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.54
_cell_length_b   4.11
_cell_length_c   7.84
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Tl3As
_chemical_formula_sum   'Tl3 As1'
_cell_volume   114.14
_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  Tl1  1  0.77  0.05  0.16  1.0
  Tl  Tl2  1  0.0  0.0  0.92  1.0
  Tl  Tl3  1  0.77  0.05  0.68  1.0
  As  As0  1  0.0  0.0  0.0  1.0

data_Tl3As
_symmetry_space_group_name_H-M   P1
_cell_length_a   3.54
_cell_length_b   4.11
_cell_length_c   7.84
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Tl3As
_chemical_formula_sum   'Tl3 As1'
_cell_volume   114.14
_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  0.92  1.0
  Tl  Tl1  1  0.77  0.05  0.16  1.0
  Tl  Tl2  1  0.77  0.05  0.68  1.0
  As  As3  1  0.0  0.0  0.0  1.0

Tl Tl Tl As
Tl Tl Tl As 0 3 + o o 1 3 o o + 1 2 - o o 
Tl3As crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one Tl3As cluster. There are three inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a single-bond geometry to one As(1) atom. The Tl(1)-As(1) bond length is 1.49 Å. In the second Tl site, Tl(2) is bonded in a single-bond geometry to one Tl(3) and one As(1) atom. The Tl(2)-Tl(3) bond length is 2.04 Å. The Tl(2)-As(1) bond length is 0.62 Å. In the third Tl site, Tl(3) is bonded in a single-bond geometry to one Tl(2) atom. As(1) is bonded in a distorted bent 150 degrees geometry to one Tl(1) and one Tl(2) atom.