data_Si2Pb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.37
_cell_length_b   6.37
_cell_length_c   6.83
_cell_angle_alpha   113.91
_cell_angle_beta   113.91
_cell_angle_gamma   33.55
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2Pb
_chemical_formula_sum   'Si4 Pb2'
_cell_volume   138.83
_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
  Si  Si2  1  0.65  0.0  0.26  1.0
  Si  Si3  1  0.52  0.0  0.39  1.0
  Si  Si4  1  0.66  0.0  0.92  1.0
  Si  Si5  1  0.79  0.0  0.79  1.0
  Pb  Pb0  1  0.41  0.0  0.48  1.0
  Pb  Pb1  1  0.91  0.0  0.71  1.0

data_Si2Pb
_symmetry_space_group_name_H-M   P-1
_cell_length_a   3.68
_cell_length_b   6.37
_cell_length_c   6.83
_cell_angle_alpha   113.91
_cell_angle_beta   90.0
_cell_angle_gamma   106.77
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Si2Pb
_chemical_formula_sum   'Si4 Pb2'
_cell_volume   138.83
_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
  Si  Si0  2  0.0  0.0  0.33  1.0
  Si  Si1  2  0.0  0.13  0.2  1.0
  Pb  Pb2  2  0.0  0.25  0.11  1.0

Si Si Si Si Pb Pb