data_BiPb2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.72
_cell_length_b   3.72
_cell_length_c   8.45
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BiPb2Se
_chemical_formula_sum   'Bi1 Pb2 Se1'
_cell_volume   116.64
_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
  Bi  Bi0  1  0.0  0.0  0.22  1.0
  Pb  Pb1  1  0.86  0.86  0.62  1.0
  Pb  Pb2  1  0.86  0.86  0.83  1.0
  Se  Se3  1  0.0  0.0  0.0  1.0

data_BiPb2Se
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.26
_cell_length_b   5.26
_cell_length_c   8.45
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   BiPb2Se
_chemical_formula_sum   'Bi2 Pb4 Se2'
_cell_volume   233.27
_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
  Bi  Bi0  2  0.0  0.0  0.22  1.0
  Pb  Pb1  2  0.36  0.5  0.62  1.0
  Pb  Pb2  2  0.36  0.5  0.83  1.0
  Se  Se3  2  0.0  0.0  0.0  1.0

Bi Pb Pb Se
Bi Pb Pb Se 0 3 o o o 1 2 o o o 2 3 + + + 