The compound described by SiO2 crystallizes in the trigonal R-3m 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(1) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. In the second O site, O(2) 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 water-like geometry to two equivalent Si(1) atoms. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.783
_cell_length_b   10.783
_cell_length_c   10.783
_cell_angle_alpha   115.246
_cell_angle_beta   115.246
_cell_angle_gamma   115.246
_symmetry_Int_Tables_number   1
_cell_volume   685.691
_cell_formula_units_Z   12
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  0.630  0.790  0.230  1.0
  Si  Si1  1  0.790  0.230  0.630  1.0
  Si  Si2  1  0.790  0.630  0.230  1.0
  Si  Si3  1  0.370  0.770  0.210  1.0
  Si  Si4  1  0.230  0.790  0.630  1.0
  Si  Si5  1  0.770  0.370  0.210  1.0
  Si  Si6  1  0.230  0.630  0.790  1.0
  Si  Si7  1  0.210  0.770  0.370  1.0
  Si  Si8  1  0.770  0.210  0.370  1.0
  Si  Si9  1  0.630  0.230  0.790  1.0
  Si  Si10  1  0.370  0.210  0.770  1.0
  Si  Si11  1  0.210  0.370  0.770  1.0
  O  O12  1  0.188  0.673  0.188  1.0
  O  O13  1  0.285  0.715  0.000  1.0
  O  O14  1  0.000  0.285  0.715  1.0
  O  O15  1  0.436  0.564  0.000  1.0
  O  O16  1  0.715  0.000  0.285  1.0
  O  O17  1  0.673  0.188  0.188  1.0
  O  O18  1  0.327  0.812  0.812  1.0
  O  O19  1  0.275  0.725  0.500  1.0
  O  O20  1  0.725  0.500  0.275  1.0
  O  O21  1  0.812  0.812  0.327  1.0
  O  O22  1  0.812  0.327  0.812  1.0
  O  O23  1  0.000  0.564  0.436  1.0
  O  O24  1  0.564  0.436  0.000  1.0
  O  O25  1  0.725  0.275  0.500  1.0
  O  O26  1  0.436  0.000  0.564  1.0
  O  O27  1  0.285  0.000  0.715  1.0
  O  O28  1  0.500  0.725  0.275  1.0
  O  O29  1  0.564  0.000  0.436  1.0
  O  O30  1  0.500  0.275  0.725  1.0
  O  O31  1  0.188  0.188  0.673  1.0
  O  O32  1  0.715  0.285  0.000  1.0
  O  O33  1  0.000  0.715  0.285  1.0
  O  O34  1  0.275  0.500  0.725  1.0
  O  O35  1  0.000  0.436  0.564  1.0
[/CIF]
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The compound described by SiO2 crystallizes in the trigonal R-3m 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(1) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. In the second O site, O(2) 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 water-like geometry to two equivalent Si(1) atoms. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.783
_cell_length_b   10.783
_cell_length_c   10.783
_cell_angle_alpha   115.246
_cell_angle_beta   115.246
_cell_angle_gamma   115.246
_symmetry_Int_Tables_number   1
_cell_volume   685.691
_cell_formula_units_Z   12
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  0.630  0.790  0.230  1.0
  Si  Si1  1  0.790  0.230  0.630  1.0
  Si  Si2  1  0.790  0.630  0.230  1.0
  Si  Si3  1  0.370  0.770  0.210  1.0
  Si  Si4  1  0.230  0.790  0.630  1.0
  Si  Si5  1  0.770  0.370  0.210  1.0
  Si  Si6  1  0.230  0.630  0.790  1.0
  Si  Si7  1  0.210  0.770  0.370  1.0
  Si  Si8  1  0.770  0.210  0.370  1.0
  Si  Si9  1  0.630  0.230  0.790  1.0
  Si  Si10  1  0.370  0.210  0.770  1.0
  Si  Si11  1  0.210  0.370  0.770  1.0
  O  O12  1  0.188  0.673  0.188  1.0
  O  O13  1  0.285  0.715  0.000  1.0
  O  O14  1  0.000  0.285  0.715  1.0
  O  O15  1  0.436  0.564  0.000  1.0
  O  O16  1  0.715  0.000  0.285  1.0
  O  O17  1  0.673  0.188  0.188  1.0
  O  O18  1  0.327  0.812  0.812  1.0
  O  O19  1  0.275  0.725  0.500  1.0
  O  O20  1  0.725  0.500  0.275  1.0
  O  O21  1  0.812  0.812  0.327  1.0
  O  O22  1  0.812  0.327  0.812  1.0
  O  O23  1  0.000  0.564  0.436  1.0
  O  O24  1  0.564  0.436  0.000  1.0
  O  O25  1  0.725  0.275  0.500  1.0
  O  O26  1  0.436  0.000  0.564  1.0
  O  O27  1  0.285  0.000  0.715  1.0
  O  O28  1  0.500  0.725  0.275  1.0
  O  O29  1  0.564  0.000  0.436  1.0
  O  O30  1  0.500  0.275  0.725  1.0
  O  O31  1  0.188  0.188  0.673  1.0
  O  O32  1  0.715  0.285  0.000  1.0
  O  O33  1  0.000  0.715  0.285  1.0
  O  O34  1  0.275  0.500  0.725  1.0
  O  O35  1  0.000  0.436  0.564  1.0
[/CIF]
.