The structure described by SiO2 crystallizes in the tetragonal I4_1/amd space group. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing SiO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(2) is bonded in a linear geometry to two equivalent Si(1) atoms. In the second O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.930
_cell_length_b   9.930
_cell_length_c   12.556
_cell_angle_alpha   113.270
_cell_angle_beta   113.269
_cell_angle_gamma   90.015
_symmetry_Int_Tables_number   1
_cell_volume   1026.786
_cell_formula_units_Z   16
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  0.044  0.107  0.391  1.0
  Si  Si1  1  0.893  0.653  0.109  1.0
  Si  Si2  1  0.044  0.783  0.391  1.0
  Si  Si3  1  0.783  0.347  0.891  1.0
  Si  Si4  1  0.217  0.653  0.109  1.0
  Si  Si5  1  0.783  0.044  0.891  1.0
  Si  Si6  1  0.107  0.347  0.891  1.0
  Si  Si7  1  0.107  0.044  0.891  1.0
  Si  Si8  1  0.347  0.783  0.391  1.0
  Si  Si9  1  0.347  0.107  0.391  1.0
  Si  Si10  1  0.956  0.893  0.609  1.0
  Si  Si11  1  0.653  0.217  0.609  1.0
  Si  Si12  1  0.217  0.956  0.109  1.0
  Si  Si13  1  0.893  0.956  0.109  1.0
  Si  Si14  1  0.653  0.893  0.609  1.0
  Si  Si15  1  0.956  0.217  0.609  1.0
  O  O16  1  0.739  0.207  0.913  1.0
  O  O17  1  0.348  0.949  0.397  1.0
  O  O18  1  0.050  0.949  0.397  1.0
  O  O19  1  0.652  0.051  0.603  1.0
  O  O20  1  0.051  0.950  0.103  1.0
  O  O21  1  0.793  0.826  0.587  1.0
  O  O22  1  0.949  0.050  0.897  1.0
  O  O23  1  0.221  0.500  1.000  1.0
  O  O24  1  0.500  0.221  0.500  1.0
  O  O25  1  0.919  0.669  0.250  1.0
  O  O26  1  0.793  0.261  0.587  1.0
  O  O27  1  0.950  0.051  0.603  1.0
  O  O28  1  0.949  0.348  0.897  1.0
  O  O29  1  0.051  0.652  0.103  1.0
  O  O30  1  0.331  0.081  0.250  1.0
  O  O31  1  0.081  0.331  0.750  1.0
  O  O32  1  0.000  0.221  0.500  1.0
  O  O33  1  0.261  0.793  0.087  1.0
  O  O34  1  0.669  0.331  0.750  1.0
  O  O35  1  1.000  0.779  0.500  1.0
  O  O36  1  0.207  0.739  0.413  1.0
  O  O37  1  0.826  0.793  0.087  1.0
  O  O38  1  0.331  0.669  0.250  1.0
  O  O39  1  0.081  0.919  0.750  1.0
  O  O40  1  0.174  0.207  0.913  1.0
  O  O41  1  0.779  1.000  0.000  1.0
  O  O42  1  0.919  0.081  0.250  1.0
  O  O43  1  0.669  0.919  0.750  1.0
  O  O44  1  0.207  0.174  0.413  1.0
  O  O45  1  0.221  0.000  1.000  1.0
  O  O46  1  0.500  0.779  0.500  1.0
  O  O47  1  0.779  0.500  0.000  1.0
[/CIF]
.
The structure described by SiO2 crystallizes in the tetragonal I4_1/amd space group. Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing SiO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(2) is bonded in a linear geometry to two equivalent Si(1) atoms. In the second O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.930
_cell_length_b   9.930
_cell_length_c   12.556
_cell_angle_alpha   113.270
_cell_angle_beta   113.269
_cell_angle_gamma   90.015
_symmetry_Int_Tables_number   1
_cell_volume   1026.786
_cell_formula_units_Z   16
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  0.044  0.107  0.391  1.0
  Si  Si1  1  0.893  0.653  0.109  1.0
  Si  Si2  1  0.044  0.783  0.391  1.0
  Si  Si3  1  0.783  0.347  0.891  1.0
  Si  Si4  1  0.217  0.653  0.109  1.0
  Si  Si5  1  0.783  0.044  0.891  1.0
  Si  Si6  1  0.107  0.347  0.891  1.0
  Si  Si7  1  0.107  0.044  0.891  1.0
  Si  Si8  1  0.347  0.783  0.391  1.0
  Si  Si9  1  0.347  0.107  0.391  1.0
  Si  Si10  1  0.956  0.893  0.609  1.0
  Si  Si11  1  0.653  0.217  0.609  1.0
  Si  Si12  1  0.217  0.956  0.109  1.0
  Si  Si13  1  0.893  0.956  0.109  1.0
  Si  Si14  1  0.653  0.893  0.609  1.0
  Si  Si15  1  0.956  0.217  0.609  1.0
  O  O16  1  0.739  0.207  0.913  1.0
  O  O17  1  0.348  0.949  0.397  1.0
  O  O18  1  0.050  0.949  0.397  1.0
  O  O19  1  0.652  0.051  0.603  1.0
  O  O20  1  0.051  0.950  0.103  1.0
  O  O21  1  0.793  0.826  0.587  1.0
  O  O22  1  0.949  0.050  0.897  1.0
  O  O23  1  0.221  0.500  1.000  1.0
  O  O24  1  0.500  0.221  0.500  1.0
  O  O25  1  0.919  0.669  0.250  1.0
  O  O26  1  0.793  0.261  0.587  1.0
  O  O27  1  0.950  0.051  0.603  1.0
  O  O28  1  0.949  0.348  0.897  1.0
  O  O29  1  0.051  0.652  0.103  1.0
  O  O30  1  0.331  0.081  0.250  1.0
  O  O31  1  0.081  0.331  0.750  1.0
  O  O32  1  0.000  0.221  0.500  1.0
  O  O33  1  0.261  0.793  0.087  1.0
  O  O34  1  0.669  0.331  0.750  1.0
  O  O35  1  1.000  0.779  0.500  1.0
  O  O36  1  0.207  0.739  0.413  1.0
  O  O37  1  0.826  0.793  0.087  1.0
  O  O38  1  0.331  0.669  0.250  1.0
  O  O39  1  0.081  0.919  0.750  1.0
  O  O40  1  0.174  0.207  0.913  1.0
  O  O41  1  0.779  1.000  0.000  1.0
  O  O42  1  0.919  0.081  0.250  1.0
  O  O43  1  0.669  0.919  0.750  1.0
  O  O44  1  0.207  0.174  0.413  1.0
  O  O45  1  0.221  0.000  1.000  1.0
  O  O46  1  0.500  0.779  0.500  1.0
  O  O47  1  0.779  0.500  0.000  1.0
[/CIF]
.