The compound described by SiO2 is Low Tridymite-like structured and crystallizes in the tetragonal I4_1/amd space group. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to four equivalent O(3) atoms to form corner-sharing SiO4 tetrahedra. There are three inequivalent O sites. In the first O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(1) is bonded in a linear geometry to two equivalent Si(1) atoms. In the third O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.434
_cell_length_b   10.282
_cell_length_c   10.282
_cell_angle_alpha   84.382
_cell_angle_beta   71.767
_cell_angle_gamma   71.767
_symmetry_Int_Tables_number   1
_cell_volume   613.557
_cell_formula_units_Z   10
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
  O  O0  1  0.000  0.000  0.000  1.0
  O  O1  1  0.000  0.000  0.500  1.0
  O  O2  1  0.500  0.500  1.000  1.0
  O  O3  1  0.000  0.500  0.500  1.0
  O  O4  1  0.221  0.750  0.059  1.0
  O  O5  1  0.971  0.059  0.750  1.0
  O  O6  1  0.779  0.441  0.750  1.0
  O  O7  1  0.029  0.750  0.441  1.0
  O  O8  1  0.779  0.250  0.941  1.0
  O  O9  1  0.029  0.941  0.250  1.0
  O  O10  1  0.221  0.559  0.250  1.0
  O  O11  1  0.971  0.250  0.559  1.0
  O  O12  1  0.769  0.846  0.154  1.0
  O  O13  1  0.614  0.154  0.654  1.0
  O  O14  1  0.423  0.346  0.846  1.0
  O  O15  1  0.231  0.154  0.846  1.0
  O  O16  1  0.231  0.346  0.654  1.0
  O  O17  1  0.769  0.654  0.346  1.0
  O  O18  1  0.386  0.846  0.346  1.0
  O  O19  1  0.577  0.654  0.154  1.0
  Si  Si20  1  0.005  0.885  0.115  1.0
  Si  Si21  1  0.890  0.115  0.615  1.0
  Si  Si22  1  0.620  0.385  0.885  1.0
  Si  Si23  1  0.995  0.115  0.885  1.0
  Si  Si24  1  0.995  0.385  0.615  1.0
  Si  Si25  1  0.005  0.615  0.385  1.0
  Si  Si26  1  0.110  0.885  0.385  1.0
  Si  Si27  1  0.380  0.615  0.115  1.0
  Si  Si28  1  0.625  0.750  0.250  1.0
  Si  Si29  1  0.375  0.250  0.750  1.0
[/CIF]
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The compound described by SiO2 is Low Tridymite-like structured and crystallizes in the tetragonal I4_1/amd space group. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to four equivalent O(3) atoms to form corner-sharing SiO4 tetrahedra. There are three inequivalent O sites. In the first O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(1) is bonded in a linear geometry to two equivalent Si(1) atoms. In the third O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.434
_cell_length_b   10.282
_cell_length_c   10.282
_cell_angle_alpha   84.382
_cell_angle_beta   71.767
_cell_angle_gamma   71.767
_symmetry_Int_Tables_number   1
_cell_volume   613.557
_cell_formula_units_Z   10
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
  O  O0  1  0.000  0.000  0.000  1.0
  O  O1  1  0.000  0.000  0.500  1.0
  O  O2  1  0.500  0.500  1.000  1.0
  O  O3  1  0.000  0.500  0.500  1.0
  O  O4  1  0.221  0.750  0.059  1.0
  O  O5  1  0.971  0.059  0.750  1.0
  O  O6  1  0.779  0.441  0.750  1.0
  O  O7  1  0.029  0.750  0.441  1.0
  O  O8  1  0.779  0.250  0.941  1.0
  O  O9  1  0.029  0.941  0.250  1.0
  O  O10  1  0.221  0.559  0.250  1.0
  O  O11  1  0.971  0.250  0.559  1.0
  O  O12  1  0.769  0.846  0.154  1.0
  O  O13  1  0.614  0.154  0.654  1.0
  O  O14  1  0.423  0.346  0.846  1.0
  O  O15  1  0.231  0.154  0.846  1.0
  O  O16  1  0.231  0.346  0.654  1.0
  O  O17  1  0.769  0.654  0.346  1.0
  O  O18  1  0.386  0.846  0.346  1.0
  O  O19  1  0.577  0.654  0.154  1.0
  Si  Si20  1  0.005  0.885  0.115  1.0
  Si  Si21  1  0.890  0.115  0.615  1.0
  Si  Si22  1  0.620  0.385  0.885  1.0
  Si  Si23  1  0.995  0.115  0.885  1.0
  Si  Si24  1  0.995  0.385  0.615  1.0
  Si  Si25  1  0.005  0.615  0.385  1.0
  Si  Si26  1  0.110  0.885  0.385  1.0
  Si  Si27  1  0.380  0.615  0.115  1.0
  Si  Si28  1  0.625  0.750  0.250  1.0
  Si  Si29  1  0.375  0.250  0.750  1.0
[/CIF]
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