data_NbCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.71
_cell_length_b   2.71
_cell_length_c   8.36
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   98.74
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NbCu
_chemical_formula_sum   'Nb2 Cu2'
_cell_volume   60.62
_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
  Nb  Nb2  1  0.76  0.97  0.96  1.0
  Nb  Nb3  1  0.76  0.03  0.4  1.0
  Cu  Cu0  1  0.76  0.97  0.49  1.0
  Cu  Cu1  1  0.76  0.03  0.88  1.0

data_NbCu
_symmetry_space_group_name_H-M   P-1
_cell_length_a   2.71
_cell_length_b   2.71
_cell_length_c   8.36
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   98.74
_symmetry_Int_Tables_number   2
_chemical_formula_structural   NbCu
_chemical_formula_sum   'Nb2 Cu2'
_cell_volume   60.62
_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
  Nb  Nb0  2  0.5  0.03  0.22  1.0
  Cu  Cu1  2  0.5  0.03  0.7  1.0

Nb Nb Cu Cu