data_Si2NiPb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.87
_cell_length_b   4.87
_cell_length_c   4.87
_cell_angle_alpha   126.92
_cell_angle_beta   126.92
_cell_angle_gamma   78.39
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2NiPb
_chemical_formula_sum   'Si2 Ni1 Pb1'
_cell_volume   71.4
_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  Si2  1  0.0  0.0  0.0  1.0
  Si  Si3  1  0.18  0.0  0.89  1.0
  Ni  Ni0  1  0.0  0.0  0.77  1.0
  Pb  Pb1  1  0.0  0.18  0.89  1.0

data_Si2NiPb
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.35
_cell_length_b   4.35
_cell_length_c   4.87
_cell_angle_alpha   116.54
_cell_angle_beta   116.54
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si2NiPb
_chemical_formula_sum   'Si2 Ni1 Pb1'
_cell_volume   71.4
_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  Si0  1  0.0  0.0  0.0  1.0
  Si  Si1  1  0.11  0.0  0.29  1.0
  Ni  Ni2  1  0.23  0.0  0.23  1.0
  Pb  Pb3  1  0.29  0.18  0.29  1.0

Si Si Ni Pb