The structure described by SiO2 crystallizes in the tetragonal P-4c2 space group. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Si(1) atoms. In the second O site, O(3) is bonded in a linear geometry to two equivalent Si(1) atoms. In the third O site, O(2) is bonded in a bent 120 degrees 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   6.601
_cell_length_b   6.601
_cell_length_c   8.138
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   354.644
_cell_formula_units_Z   8
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  0.461  0.760  0.404  1.0
  Si  Si1  1  0.539  0.760  0.904  1.0
  Si  Si2  1  0.760  0.539  0.596  1.0
  Si  Si3  1  0.240  0.461  0.596  1.0
  Si  Si4  1  0.760  0.461  0.096  1.0
  Si  Si5  1  0.461  0.240  0.904  1.0
  Si  Si6  1  0.240  0.539  0.096  1.0
  Si  Si7  1  0.539  0.240  0.404  1.0
  O  O8  1  0.675  0.675  0.750  1.0
  O  O9  1  0.666  0.309  0.570  1.0
  O  O10  1  0.666  0.691  0.070  1.0
  O  O11  1  0.500  0.000  0.887  1.0
  O  O12  1  0.691  0.334  0.930  1.0
  O  O13  1  0.675  0.325  0.250  1.0
  O  O14  1  0.309  0.334  0.430  1.0
  O  O15  1  0.334  0.691  0.570  1.0
  O  O16  1  0.309  0.666  0.930  1.0
  O  O17  1  0.325  0.675  0.250  1.0
  O  O18  1  0.325  0.325  0.750  1.0
  O  O19  1  0.000  0.500  0.113  1.0
  O  O20  1  0.500  0.000  0.387  1.0
  O  O21  1  0.691  0.666  0.430  1.0
  O  O22  1  0.334  0.309  0.070  1.0
  O  O23  1  0.000  0.500  0.613  1.0
[/CIF]
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The structure described by SiO2 crystallizes in the tetragonal P-4c2 space group. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Si(1) atoms. In the second O site, O(3) is bonded in a linear geometry to two equivalent Si(1) atoms. In the third O site, O(2) is bonded in a bent 120 degrees 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   6.601
_cell_length_b   6.601
_cell_length_c   8.138
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   354.644
_cell_formula_units_Z   8
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  0.461  0.760  0.404  1.0
  Si  Si1  1  0.539  0.760  0.904  1.0
  Si  Si2  1  0.760  0.539  0.596  1.0
  Si  Si3  1  0.240  0.461  0.596  1.0
  Si  Si4  1  0.760  0.461  0.096  1.0
  Si  Si5  1  0.461  0.240  0.904  1.0
  Si  Si6  1  0.240  0.539  0.096  1.0
  Si  Si7  1  0.539  0.240  0.404  1.0
  O  O8  1  0.675  0.675  0.750  1.0
  O  O9  1  0.666  0.309  0.570  1.0
  O  O10  1  0.666  0.691  0.070  1.0
  O  O11  1  0.500  0.000  0.887  1.0
  O  O12  1  0.691  0.334  0.930  1.0
  O  O13  1  0.675  0.325  0.250  1.0
  O  O14  1  0.309  0.334  0.430  1.0
  O  O15  1  0.334  0.691  0.570  1.0
  O  O16  1  0.309  0.666  0.930  1.0
  O  O17  1  0.325  0.675  0.250  1.0
  O  O18  1  0.325  0.325  0.750  1.0
  O  O19  1  0.000  0.500  0.113  1.0
  O  O20  1  0.500  0.000  0.387  1.0
  O  O21  1  0.691  0.666  0.430  1.0
  O  O22  1  0.334  0.309  0.070  1.0
  O  O23  1  0.000  0.500  0.613  1.0
[/CIF]
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