data_Cu2Ag
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.55
_cell_length_b   4.16
_cell_length_c   7.2
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Cu2Ag
_chemical_formula_sum   'Cu4 Ag2'
_cell_volume   76.24
_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  Cu2  1  0.0  0.0  0.0  1.0
  Cu  Cu3  1  0.85  0.0  0.4  1.0
  Cu  Cu4  1  0.0  0.08  0.6  1.0
  Cu  Cu5  1  0.7  0.0  0.8  1.0
  Ag  Ag0  1  0.85  0.08  0.0  1.0
  Ag  Ag1  1  0.7  0.08  0.2  1.0

data_Cu2Ag
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.55
_cell_length_b   4.16
_cell_length_c   7.2
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Cu2Ag
_chemical_formula_sum   'Cu4 Ag2'
_cell_volume   76.24
_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  0.0  1.0
  Cu  Cu1  1  0.0  0.08  0.6  1.0
  Cu  Cu2  1  0.7  0.0  0.8  1.0
  Cu  Cu3  1  0.85  0.0  0.4  1.0
  Ag  Ag4  1  0.7  0.08  0.2  1.0
  Ag  Ag5  1  0.85  0.08  0.0  1.0

Cu Cu Cu Cu Ag Ag
Cu Cu Cu Cu Ag Ag 0 4 - o o 0 3 - o - 0 5 - o o 1 5 o o o 1 2 + o o 2 3 - o o 3 4 o o + 4 5 o o o 