data_[Rb2Na2Nb2O6]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Rb  0.8200  2.3500  1.6600
  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 [P-1]
_cell_length_a [5.5984]
_cell_length_b [6.1853]
_cell_length_c [6.4960]
_cell_angle_alpha [62.7187]
_cell_angle_beta [82.2624]
_cell_angle_gamma [81.2529]
_symmetry_Int_Tables_number [2]
_chemical_formula_structural [RbNaNbO3]
_chemical_formula_sum '[Rb2 Na2 Nb2 O6]'
_cell_volume [197.0542]
_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
[
  Rb  Rb0  2  0.2565  0.7246  0.5416  1.0
  Na  Na1  2  0.2518  0.4263  0.1495  1.0
  Nb  Nb2  2  0.2307  0.0432  0.9033  1.0
  O  O3  2  0.0021  0.7848  0.9317  1.0
  O  O4  2  0.2308  0.2231  0.5798  1.0
  O  O5  2  0.4830  0.7636  0.0600  1.0
]