data_[Na6Mg4Nb2O12]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Mg  1.3100  1.5000  0.8600
  Nb  1.6000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [5.3812]
_cell_length_b [9.3205]
_cell_length_c [5.7385]
_cell_angle_alpha [90.0000]
_cell_angle_beta [108.2274]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [Na3Mg2NbO6]
_chemical_formula_sum '[Na6 Mg4 Nb2 O12]'
_cell_volume [273.3727]
_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  Na0  4  0.0000  0.1715  0.5000  1
  Na  Na1  2  0.0000  0.5000  0.5000  1
  Mg  Mg2  4  0.0000  0.3336  0.0000  1
  Nb  Nb3  2  0.0000  0.0000  0.0000  1
  O  O4  8  0.2271  0.1593  0.2038  1
  O  O5  4  0.2498  0.5000  0.2030  1
]