data_[Na6Ca9Ta6O27]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Ca  1.0000  1.8000  1.1400
  Ta  1.5000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [R32]
_cell_length_a [5.7114]
_cell_length_b [5.7114]
_cell_length_c [24.5122]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [155]
_chemical_formula_structural [Na2Ca3Ta2O9]
_chemical_formula_sum '[Na6 Ca9 Ta6 O27]'
_cell_volume [692.4725]
_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  6  0.0000  0.0000  0.1976  1.0
  Ca  Ca1  6  0.0000  0.0000  0.3714  1.0
  Ca  Ca2  3  0.0000  0.0000  0.5000  1.0
  Ta  Ta3  6  0.0000  0.0000  0.0639  1.0
  O  O4  18  0.0144  0.4400  0.7723  1.0
  O  O5  9  0.0000  0.2587  0.0000  1.0
]