data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.93
_cell_length_b   5.66
_cell_length_c   5.24
_cell_angle_alpha   90.0
_cell_angle_beta   107.17
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SiO2
_chemical_formula_sum   'Si4 O8'
_cell_volume   139.63
_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  1  0.82  0.83  0.69  1.0
  Si  Si1  1  0.8  0.0  0.61  1.0
  Si  Si2  1  0.4  0.0  0.14  1.0
  Si  Si3  1  0.04  0.83  0.1  1.0
  O  O4  1  0.21  0.26  0.26  1.0
  O  O5  1  0.11  0.18  0.49  1.0
  O  O6  1  0.43  0.83  0.04  1.0
  O  O7  1  0.11  0.47  0.49  1.0
  O  O8  1  0.35  0.83  0.43  1.0
  O  O9  1  0.21  0.4  0.26  1.0
  O  O10  1  0.43  0.0  0.48  1.0
  O  O11  1  0.12  0.0  0.14  1.0

data_SiO2
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.93
_cell_length_b   5.24
_cell_length_c   5.66
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   107.17
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SiO2
_chemical_formula_sum   'Si4 O8'
_cell_volume   139.63
_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  1  0.18  0.31  0.17  1.0
  Si  Si1  1  0.2  0.39  0.0  1.0
  Si  Si2  1  0.6  0.86  0.0  1.0
  Si  Si3  1  0.96  0.9  0.17  1.0
  O  O4  1  0.57  0.96  0.17  1.0
  O  O5  1  0.57  0.52  0.0  1.0
  O  O6  1  0.65  0.57  0.17  1.0
  O  O7  1  0.79  0.74  0.6  1.0
  O  O8  1  0.79  0.74  0.74  1.0
  O  O9  1  0.88  0.86  0.0  1.0
  O  O10  1  0.89  0.51  0.53  1.0
  O  O11  1  0.89  0.51  0.82  1.0

Si Si Si Si O O O O O O O O
Si Si Si Si O O O O O O O O 0 1 o + o 2 6 o - o 3 11 o + o 4 9 o o o 4 5 o o o 5 10 o o o 5 9 o o o 5 7 o o o 7 9 o o o 8 10 o + o 