The structure described by SiO2 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form corner-sharing SiO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the fourth O site, O(4) is bonded in a linear geometry to two equivalent Si(2) atoms. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.008
_cell_length_b   11.008
_cell_length_c   11.008
_cell_angle_alpha   103.110
_cell_angle_beta   103.110
_cell_angle_gamma   123.118
_symmetry_Int_Tables_number   1
_cell_volume   982.460
_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  0.750  0.396  0.646  1.0
  Si  Si1  1  0.047  0.547  0.880  1.0
  Si  Si2  1  0.667  0.167  0.120  1.0
  Si  Si3  1  0.750  0.104  0.354  1.0
  Si  Si4  1  0.453  0.333  0.500  1.0
  Si  Si5  1  0.604  0.250  0.354  1.0
  Si  Si6  1  0.250  0.604  0.354  1.0
  Si  Si7  1  0.396  0.750  0.646  1.0
  Si  Si8  1  0.953  0.453  0.120  1.0
  Si  Si9  1  0.167  0.047  0.500  1.0
  Si  Si10  1  0.250  0.896  0.646  1.0
  Si  Si11  1  0.833  0.953  0.500  1.0
  Si  Si12  1  0.104  0.750  0.354  1.0
  Si  Si13  1  0.896  0.250  0.646  1.0
  Si  Si14  1  0.547  0.667  0.500  1.0
  Si  Si15  1  0.333  0.833  0.880  1.0
  O  O16  1  0.769  0.130  0.217  1.0
  O  O17  1  0.413  0.630  0.360  1.0
  O  O18  1  0.630  0.269  0.217  1.0
  O  O19  1  0.257  0.757  0.350  1.0
  O  O20  1  0.407  0.907  0.650  1.0
  O  O21  1  0.587  0.370  0.640  1.0
  O  O22  1  0.593  0.093  0.350  1.0
  O  O23  1  0.907  0.257  0.500  1.0
  O  O24  1  0.552  0.769  0.640  1.0
  O  O25  1  0.130  0.913  0.360  1.0
  O  O26  1  0.087  0.448  0.217  1.0
  O  O27  1  0.370  0.731  0.783  1.0
  O  O28  1  0.743  0.243  0.650  1.0
  O  O29  1  0.276  0.224  0.500  1.0
  O  O30  1  0.913  0.552  0.783  1.0
  O  O31  1  0.231  0.870  0.783  1.0
  O  O32  1  0.500  0.000  0.000  1.0
  O  O33  1  0.448  0.231  0.360  1.0
  O  O34  1  0.870  0.087  0.640  1.0
  O  O35  1  0.776  0.276  0.053  1.0
  O  O36  1  0.500  0.500  0.500  1.0
  O  O37  1  0.093  0.743  0.500  1.0
  O  O38  1  0.757  0.407  0.500  1.0
  O  O39  1  0.269  0.052  0.640  1.0
  O  O40  1  0.224  0.724  0.947  1.0
  O  O41  1  0.243  0.593  0.500  1.0
  O  O42  1  0.948  0.587  0.217  1.0
  O  O43  1  0.052  0.413  0.783  1.0
  O  O44  1  0.731  0.948  0.360  1.0
  O  O45  1  0.724  0.776  0.500  1.0
  O  O46  1  0.000  0.500  0.000  1.0
  O  O47  1  0.000  0.000  0.500  1.0
[/CIF]
.
The structure described by SiO2 crystallizes in the tetragonal I4/mcm space group. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form corner-sharing SiO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the fourth O site, O(4) is bonded in a linear geometry to two equivalent Si(2) atoms. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.008
_cell_length_b   11.008
_cell_length_c   11.008
_cell_angle_alpha   103.110
_cell_angle_beta   103.110
_cell_angle_gamma   123.118
_symmetry_Int_Tables_number   1
_cell_volume   982.460
_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  0.750  0.396  0.646  1.0
  Si  Si1  1  0.047  0.547  0.880  1.0
  Si  Si2  1  0.667  0.167  0.120  1.0
  Si  Si3  1  0.750  0.104  0.354  1.0
  Si  Si4  1  0.453  0.333  0.500  1.0
  Si  Si5  1  0.604  0.250  0.354  1.0
  Si  Si6  1  0.250  0.604  0.354  1.0
  Si  Si7  1  0.396  0.750  0.646  1.0
  Si  Si8  1  0.953  0.453  0.120  1.0
  Si  Si9  1  0.167  0.047  0.500  1.0
  Si  Si10  1  0.250  0.896  0.646  1.0
  Si  Si11  1  0.833  0.953  0.500  1.0
  Si  Si12  1  0.104  0.750  0.354  1.0
  Si  Si13  1  0.896  0.250  0.646  1.0
  Si  Si14  1  0.547  0.667  0.500  1.0
  Si  Si15  1  0.333  0.833  0.880  1.0
  O  O16  1  0.769  0.130  0.217  1.0
  O  O17  1  0.413  0.630  0.360  1.0
  O  O18  1  0.630  0.269  0.217  1.0
  O  O19  1  0.257  0.757  0.350  1.0
  O  O20  1  0.407  0.907  0.650  1.0
  O  O21  1  0.587  0.370  0.640  1.0
  O  O22  1  0.593  0.093  0.350  1.0
  O  O23  1  0.907  0.257  0.500  1.0
  O  O24  1  0.552  0.769  0.640  1.0
  O  O25  1  0.130  0.913  0.360  1.0
  O  O26  1  0.087  0.448  0.217  1.0
  O  O27  1  0.370  0.731  0.783  1.0
  O  O28  1  0.743  0.243  0.650  1.0
  O  O29  1  0.276  0.224  0.500  1.0
  O  O30  1  0.913  0.552  0.783  1.0
  O  O31  1  0.231  0.870  0.783  1.0
  O  O32  1  0.500  0.000  0.000  1.0
  O  O33  1  0.448  0.231  0.360  1.0
  O  O34  1  0.870  0.087  0.640  1.0
  O  O35  1  0.776  0.276  0.053  1.0
  O  O36  1  0.500  0.500  0.500  1.0
  O  O37  1  0.093  0.743  0.500  1.0
  O  O38  1  0.757  0.407  0.500  1.0
  O  O39  1  0.269  0.052  0.640  1.0
  O  O40  1  0.224  0.724  0.947  1.0
  O  O41  1  0.243  0.593  0.500  1.0
  O  O42  1  0.948  0.587  0.217  1.0
  O  O43  1  0.052  0.413  0.783  1.0
  O  O44  1  0.731  0.948  0.360  1.0
  O  O45  1  0.724  0.776  0.500  1.0
  O  O46  1  0.000  0.500  0.000  1.0
  O  O47  1  0.000  0.000  0.500  1.0
[/CIF]
.