data_AlCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.75
_cell_length_b   4.46
_cell_length_c   4.43
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   AlCu
_chemical_formula_sum   'Al2 Cu2'
_cell_volume   54.33
_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
  Al  Al0  1  0.0  0.0  0.68  1.0
  Al  Al1  1  0.38  0.23  0.75  1.0
  Cu  Cu2  1  0.38  0.0  0.45  1.0
  Cu  Cu3  1  0.0  0.23  0.98  1.0

data_AlCu
_symmetry_space_group_name_H-M   P-1
_cell_length_a   2.75
_cell_length_b   4.43
_cell_length_c   4.46
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   AlCu
_chemical_formula_sum   'Al2 Cu2'
_cell_volume   54.33
_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
  Al  Al0  2  0.31  0.96  0.39  1.0
  Cu  Cu1  2  0.31  0.27  0.61  1.0

Al Al Cu Cu
Al Al Cu Cu 0 2 o o o 0 3 o o o 0 1 o o o 1 3 o o o 1 2 o o o 