data_Pb2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.62
_cell_length_b   6.62
_cell_length_c   5.55
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   48.54
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Pb2Se
_chemical_formula_sum   'Pb4 Se2'
_cell_volume   182.19
_cell_formula_units_Z   2
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
  Pb  Pb0  1  0.64  0.24  0.16  1.0
  Pb  Pb1  1  0.43  0.76  0.39  1.0
  Pb  Pb2  1  0.43  0.24  0.16  1.0
  Pb  Pb3  1  0.64  0.76  0.39  1.0
  Se  Se4  1  0.04  0.7  0.16  1.0
  Se  Se5  1  0.04  0.3  0.39  1.0

data_Pb2Se
_symmetry_space_group_name_H-M   P-1
_cell_length_a   5.44
_cell_length_b   5.55
_cell_length_c   6.62
_cell_angle_alpha   90.0
_cell_angle_beta   114.27
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Pb2Se
_chemical_formula_sum   'Pb4 Se2'
_cell_volume   182.19
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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
  Pb  Pb0  2  0.24  0.89  0.63  1.0
  Pb  Pb1  2  0.24  0.89  0.85  1.0
  Se  Se2  2  0.3  0.11  0.3  1.0

Pb Pb Pb Pb Se Se