data_NaMg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.27
_cell_length_b   4.85
_cell_length_c   6.98
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaMg
_chemical_formula_sum   'Na2 Mg2'
_cell_volume   110.77
_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
  Na  Na2  1  0.0  0.0  0.93  1.0
  Na  Na3  1  0.63  0.43  0.05  1.0
  Mg  Mg0  1  0.0  0.0  0.19  1.0
  Mg  Mg1  1  0.63  0.43  0.79  1.0

data_NaMg
_symmetry_space_group_name_H-M   P-1
_cell_length_a   3.27
_cell_length_b   4.85
_cell_length_c   6.98
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   2
_chemical_formula_structural   NaMg
_chemical_formula_sum   'Na2 Mg2'
_cell_volume   110.77
_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
  Na  Na0  2  0.32  0.21  0.56  1.0
  Mg  Mg1  2  0.32  0.21  0.3  1.0

Na Na Mg Mg