data_[Ba2Si8O18]
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
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [P-6c2]
_cell_length_a [6.5768]
_cell_length_b [6.5768]
_cell_length_c [9.4662]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [120.0000]
_symmetry_Int_Tables_number [188]
_chemical_formula_structural [BaSi4O9]
_chemical_formula_sum '[Ba2 Si8 O18]'
_cell_volume [354.6020]
_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
[
  Ba  Ba0  2  0.6667  0.3333  0.5000  1
  Si  Si1  6  0.0892  0.3005  0.2500  1
  Si  Si2  2  0.3333  0.6667  0.5000  1
  O  O3  12  0.1061  0.4431  0.1070  1
  O  O4  6  0.2643  0.0774  0.7500  1
]