data_Na3Mg4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   15.4
_cell_length_b   15.4
_cell_length_c   15.4
_cell_angle_alpha   166.76
_cell_angle_beta   166.76
_cell_angle_gamma   18.77
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Na3Mg4
_chemical_formula_sum   'Na3 Mg4'
_cell_volume   191.58
_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
  Na  Na4  1  0.0  0.0  0.0  1.0
  Na  Na5  1  0.0  0.0  0.9  1.0
  Na  Na6  1  0.0  0.0  0.49  1.0
  Mg  Mg0  1  0.0  0.0  0.03  1.0
  Mg  Mg1  1  0.0  0.0  0.36  1.0
  Mg  Mg2  1  0.0  0.0  0.97  1.0
  Mg  Mg3  1  0.0  0.0  0.42  1.0

data_Na3Mg4
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.02
_cell_length_b   5.02
_cell_length_c   15.4
_cell_angle_alpha   90.0
_cell_angle_beta   99.38
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Na3Mg4
_chemical_formula_sum   'Na6 Mg8'
_cell_volume   383.17
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  0.0  0.0  0.0  1.0
  Na  Na1  2  0.0  0.0  0.1  1.0
  Na  Na2  2  0.0  0.0  0.51  1.0
  Mg  Mg3  2  0.0  0.0  0.03  1.0
  Mg  Mg4  2  0.0  0.0  0.58  1.0
  Mg  Mg5  2  0.0  0.0  0.64  1.0
  Mg  Mg6  2  0.0  0.0  0.97  1.0

Na Na Na Mg Mg Mg Mg