data_MgCu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.27
_cell_length_b   5.27
_cell_length_c   5.27
_cell_angle_alpha   144.56
_cell_angle_beta   130.78
_cell_angle_gamma   62.11
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgCu
_chemical_formula_sum   'Mg2 Cu2'
_cell_volume   63.54
_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
  Mg  Mg2  1  0.6  0.1  0.01  1.0
  Mg  Mg3  1  0.0  0.1  0.5  1.0
  Cu  Cu0  1  0.6  0.1  0.22  1.0
  Cu  Cu1  1  0.0  0.1  0.29  1.0

data_MgCu
_symmetry_space_group_name_H-M   P-1
_cell_length_a   3.21
_cell_length_b   4.39
_cell_length_c   5.27
_cell_angle_alpha   114.61
_cell_angle_beta   107.72
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   MgCu
_chemical_formula_sum   'Mg2 Cu2'
_cell_volume   63.54
_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
  Mg  Mg0  2  0.45  0.25  0.45  1.0
  Cu  Cu1  2  0.34  0.54  0.34  1.0

Mg Mg Cu Cu
Mg Mg Cu Cu 0 2 o o o 1 3 o o o 