data_CuSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.78
_cell_length_b   3.74
_cell_length_c   4.97
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CuSi
_chemical_formula_sum   'Cu2 Si2'
_cell_volume   51.71
_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
  Cu  Cu0  1  0.0  0.0  0.15  1.0
  Cu  Cu1  1  0.39  0.87  0.82  1.0
  Si  Si2  1  0.0  0.0  0.68  1.0
  Si  Si3  1  0.39  0.87  0.28  1.0

data_CuSi
_symmetry_space_group_name_H-M   P-1
_cell_length_a   2.78
_cell_length_b   3.74
_cell_length_c   4.97
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   CuSi
_chemical_formula_sum   'Cu2 Si2'
_cell_volume   51.71
_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
  Cu  Cu0  2  0.2  0.43  0.34  1.0
  Si  Si1  2  0.2  0.43  0.8  1.0

Cu Cu Si Si