data_[Ba3Si6Sn6O21]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Ba  0.8900  2.1500  1.4900
  Si  1.9000  1.1000  0.5400
  Sn  1.9600  1.4500  0.8300
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [R32]
_cell_length_a [5.4912]
_cell_length_b [5.4912]
_cell_length_c [23.1162]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [155]
_chemical_formula_structural [BaSi2Sn2O7]
_chemical_formula_sum '[Ba3 Si6 Sn6 O21]'
_cell_volume [603.6390]
_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
[
  Ba  Ba0  3  0.0000  0.0000  0.5000  1.0
  Si  Si1  6  0.0000  0.0000  0.0719  1.0
  Sn  Sn2  6  0.0000  0.0000  0.2911  1.0
  O  O3  18  0.0207  0.4298  0.5717  1.0
  O  O4  3  0.0000  0.0000  0.0000  1.0
]