data_[Na8Nb4O16]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Nb  1.6000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [P4/ncc]
_cell_length_a [8.5659]
_cell_length_b [8.5659]
_cell_length_c [5.4904]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [130]
_chemical_formula_structural [Na2NbO4]
_chemical_formula_sum '[Na8 Nb4 O16]'
_cell_volume [402.8506]
_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  Na0  8  0.1737  0.1737  0.2500  1
  Nb  Nb1  4  0.0000  0.5000  0.1251  1
  O  O2  16  0.0648  0.3175  0.9105  1
]