data_[K6Ca4Nb2O12]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  K  0.8200  2.2000  1.5200
  Ca  1.0000  1.8000  1.1400
  Nb  1.6000  1.4500  0.8200
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [C2/m]
_cell_length_a [5.9012]
_cell_length_b [10.2132]
_cell_length_c [6.4687]
_cell_angle_alpha [90.0000]
_cell_angle_beta [107.7941]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [12]
_chemical_formula_structural [K3Ca2NbO6]
_chemical_formula_sum '[K6 Ca4 Nb2 O12]'
_cell_volume [371.2203]
_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
[
  K  K0  4  0.0000  0.1682  0.5000  1
  K  K1  2  0.0000  0.5000  0.5000  1
  Ca  Ca2  4  0.0000  0.3334  0.0000  1
  Nb  Nb3  2  0.0000  0.0000  0.0000  1
  O  O4  8  0.2077  0.1458  0.1851  1
  O  O5  4  0.2293  0.0000  0.8152  1
]