data_[Na3Nd6Nb3O18]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Nd  1.1400  1.8500  1.2765
  Nb  1.6000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [R3]
_cell_length_a [5.8413]
_cell_length_b [5.8413]
_cell_length_c [14.9665]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [146]
_chemical_formula_structural [NaNd2NbO6]
_chemical_formula_sum '[Na3 Nd6 Nb3 O18]'
_cell_volume [442.2580]
_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  0.1957  1.0
  Nd  Nd1  3  0.0000  0.0000  0.4699  1.0
  Nd  Nd2  3  0.0000  0.0000  0.9693  1.0
  Nb  Nb3  3  0.0000  0.0000  0.6847  1.0
  O  O4  9  0.0143  0.3942  0.4145  1.0
  O  O5  9  0.0697  0.6753  0.2585  1.0
]