data_[Na6Zr3Nb3O18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Zr  1.3300  1.5500  0.8600
  Nb  1.6000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [R3]
_cell_length_a [5.6841]
_cell_length_b [5.6841]
_cell_length_c [14.2890]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [146]
_chemical_formula_structural [Na2ZrNbO6]
_chemical_formula_sum '[Na6 Zr3 Nb3 O18]'
_cell_volume [399.8161]
_cell_formula_units_Z [3]
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  3  0.0000  0.0000  0.4495  1.0
  Na  Na1  3  0.0000  0.0000  0.9491  1.0
  Zr  Zr2  3  0.0000  0.0000  0.1848  1.0
  Nb  Nb3  3  0.0000  0.0000  0.6882  1.0
  O  O4  9  0.0032  0.4333  0.4258  1.0
  O  O5  9  0.1099  0.7627  0.2631  1.0
]