The structure described by SiO2 is beta Tridymite structured and crystallizes in the hexagonal P6_322 space group. Si(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing SiO4 tetrahedra. There are two 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. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.069
_cell_length_b   5.069
_cell_length_c   8.558
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   190.452
_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  0.667  0.333  0.937  1.0
  Si  Si1  1  0.667  0.333  0.563  1.0
  Si  Si2  1  0.333  0.667  0.063  1.0
  Si  Si3  1  0.333  0.667  0.437  1.0
  O  O4  1  0.000  0.421  0.000  1.0
  O  O5  1  0.421  0.421  0.500  1.0
  O  O6  1  0.579  0.000  0.500  1.0
  O  O7  1  0.579  0.579  0.000  1.0
  O  O8  1  0.000  0.579  0.500  1.0
  O  O9  1  0.667  0.333  0.750  1.0
  O  O10  1  0.333  0.667  0.250  1.0
  O  O11  1  0.421  0.000  0.000  1.0
[/CIF]
.
The structure described by SiO2 is beta Tridymite structured and crystallizes in the hexagonal P6_322 space group. Si(1) is bonded to one O(2) and three equivalent O(1) atoms to form corner-sharing SiO4 tetrahedra. There are two 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. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.069
_cell_length_b   5.069
_cell_length_c   8.558
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   190.452
_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  0.667  0.333  0.937  1.0
  Si  Si1  1  0.667  0.333  0.563  1.0
  Si  Si2  1  0.333  0.667  0.063  1.0
  Si  Si3  1  0.333  0.667  0.437  1.0
  O  O4  1  0.000  0.421  0.000  1.0
  O  O5  1  0.421  0.421  0.500  1.0
  O  O6  1  0.579  0.000  0.500  1.0
  O  O7  1  0.579  0.579  0.000  1.0
  O  O8  1  0.000  0.579  0.500  1.0
  O  O9  1  0.667  0.333  0.750  1.0
  O  O10  1  0.333  0.667  0.250  1.0
  O  O11  1  0.421  0.000  0.000  1.0
[/CIF]
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