data_Na2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.21
_cell_length_b   4.77
_cell_length_c   10.81
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na2Mg
_chemical_formula_sum   'Na8 Mg4'
_cell_volume   371.8
_cell_formula_units_Z   4
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
  Na  Na4  1  0.94  0.19  0.75  1.0
  Na  Na5  1  0.91  0.19  0.38  1.0
  Na  Na6  1  0.7  0.58  0.98  1.0
  Na  Na7  1  0.67  0.58  0.15  1.0
  Na  Na8  1  0.54  0.19  0.66  1.0
  Na  Na9  1  0.51  0.19  0.83  1.0
  Na  Na10  1  0.31  0.58  0.42  1.0
  Na  Na11  1  0.28  0.58  0.06  1.0
  Mg  Mg0  1  0.79  0.19  0.08  1.0
  Mg  Mg1  1  0.82  0.58  0.68  1.0
  Mg  Mg2  1  0.39  0.19  0.13  1.0
  Mg  Mg3  1  0.43  0.58  0.73  1.0

data_Na2Mg
_symmetry_space_group_name_H-M   P-1
_cell_length_a   4.77
_cell_length_b   7.21
_cell_length_c   10.81
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Na2Mg
_chemical_formula_sum   'Na8 Mg4'
_cell_volume   371.8
_cell_formula_units_Z   4
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
  Na  Na0  2  0.31  0.3  0.48  1.0
  Na  Na1  2  0.31  0.33  0.84  1.0
  Na  Na2  2  0.31  0.91  0.92  1.0
  Na  Na3  2  0.31  0.94  0.75  1.0
  Mg  Mg4  2  0.31  0.18  0.18  1.0
  Mg  Mg5  2  0.31  0.79  0.23  1.0

Na Na Na Na Na Na Na Na Mg Mg Mg Mg