data_[Na8Si12O28]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Na  0.9300  1.8000  1.1600
  Si  1.9000  1.1000  0.5400
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [C2/c]
_cell_length_a [8.9260]
_cell_length_b [4.8315]
_cell_length_c [11.4535]
_cell_angle_alpha [90.0000]
_cell_angle_beta [102.5475]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [15]
_chemical_formula_structural [Na2Si3O7]
_chemical_formula_sum '[Na8 Si12 O28]'
_cell_volume [482.1442]
_cell_formula_units_Z [4]
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  8  0.1487  0.2971  0.6839  1
  Si  Si1  8  0.0424  0.2138  0.3854  1
  Si  Si2  4  0.2500  0.2500  0.0000  1
  O  O3  8  0.1249  0.1247  0.0902  1
  O  O4  8  0.1351  0.4500  0.4685  1
  O  O5  8  0.1389  0.0678  0.8693  1
  O  O6  4  0.0000  0.3608  0.2500  1
]