data_MgCu3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.6
_cell_length_b   4.6
_cell_length_c   4.56
_cell_angle_alpha   101.62
_cell_angle_beta   101.62
_cell_angle_gamma   34.9
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgCu3
_chemical_formula_sum   'Mg1 Cu3'
_cell_volume   53.94
_cell_formula_units_Z   1
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  Mg3  1  0.0  0.0  0.0  1.0
  Cu  Cu0  1  0.38  0.0  0.18  1.0
  Cu  Cu1  1  0.42  0.0  0.28  1.0
  Cu  Cu2  1  0.9  0.0  0.23  1.0

data_MgCu3
_symmetry_space_group_name_H-M   P1
_cell_length_a   2.76
_cell_length_b   4.56
_cell_length_c   4.6
_cell_angle_alpha   101.62
_cell_angle_beta   107.45
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgCu3
_chemical_formula_sum   'Mg1 Cu3'
_cell_volume   53.94
_cell_formula_units_Z   1
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  Mg0  1  0.0  0.0  0.0  1.0
  Cu  Cu1  1  0.0  0.18  0.38  1.0
  Cu  Cu2  1  0.0  0.23  0.9  1.0
  Cu  Cu3  1  0.0  0.28  0.42  1.0

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