data_Sb2PbSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.62
_cell_length_b   3.62
_cell_length_c   8.22
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sb2PbSe
_chemical_formula_sum   'Sb2 Pb1 Se1'
_cell_volume   107.39
_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
  Sb  Sb1  1  0.81  0.81  0.42  1.0
  Sb  Sb2  1  0.81  0.81  0.8  1.0
  Pb  Pb0  1  0.0  0.0  0.11  1.0
  Se  Se3  1  0.0  0.0  0.0  1.0

data_Sb2PbSe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.11
_cell_length_b   5.11
_cell_length_c   8.22
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Sb2PbSe
_chemical_formula_sum   'Sb4 Pb2 Se2'
_cell_volume   214.78
_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
  Sb  Sb0  2  0.31  0.5  0.42  1.0
  Sb  Sb1  2  0.31  0.5  0.8  1.0
  Pb  Pb2  2  0.0  0.0  0.11  1.0
  Se  Se3  2  0.0  0.0  0.0  1.0

Sb Sb Pb Se
Sb Sb Pb Se 0 0 + o o 0 0 o + o 0 3 + + o 0 2 + + o 0 1 o o o 1 3 + + + 2 3 o o o 
PbSb2Se crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two PbSb2Se clusters. Pb(1) is bonded in a distorted single-bond geometry to one Sb(1) and one Se(1) atom. The Pb(1)-Sb(1) bond length is 2.72 Å. The Pb(1)-Se(1) bond length is 0.89 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a distorted single-bond geometry to one Pb(1) atom. In the second Sb site, Sb(2) is bonded in a single-bond geometry to one Se(1) atom. The Sb(2)-Se(1) bond length is 1.92 Å. Se(1) is bonded in a bent 150 degrees geometry to one Pb(1) and one Sb(2) atom.