data_SiPb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.46
_cell_length_b   5.46
_cell_length_c   5.46
_cell_angle_alpha   35.76
_cell_angle_beta   35.76
_cell_angle_gamma   35.76
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SiPb
_chemical_formula_sum   'Si1 Pb1'
_cell_volume   49.76
_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
  Si  Si1  1  0.0  0.0  0.0  1.0
  Pb  Pb0  1  0.0  0.0  0.66  1.0

data_SiPb
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.81
_cell_length_b   3.35
_cell_length_c   5.46
_cell_angle_alpha   90.0
_cell_angle_beta   110.77
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   SiPb
_chemical_formula_sum   'Si2 Pb2'
_cell_volume   99.52
_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
  Si  Si0  2  0.0  0.0  0.0  1.0
  Pb  Pb1  2  0.0  0.0  0.34  1.0

Si Pb
Si Pb 0 1 o o - 