data_[Si4O8]
loop_
 _atom_type_symbol
 _atom_type_electronegativity
 _atom_type_radius
 _atom_type_ionic_radius
[
  Si  1.9000  1.1000  0.5400
  O  3.4400  0.6000  1.2600
]
_symmetry_space_group_name_H-M [Pmma]
_cell_length_a [8.1697]
_cell_length_b [2.8154]
_cell_length_c [19.4720]
_cell_angle_alpha [90.0000]
_cell_angle_beta [90.0000]
_cell_angle_gamma [90.0000]
_symmetry_Int_Tables_number [51]
_chemical_formula_structural [SiO2]
_chemical_formula_sum '[Si4 O8]'
_cell_volume [447.8788]
_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
[
  Si  Si0  4  0.0522  0.5000  0.0802  1
  O  O1  4  0.0153  0.0000  0.8856  1
  O  O2  2  0.0000  0.5000  0.0000  1
  O  O3  2  0.2500  0.5000  0.0864  1
]