The structure described by SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic P2_1/c space group. Si(1,2) 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 150 degrees geometry to two equivalent Si(1,2) atoms. In the second O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(1,2) atoms. In the third O site, O(3) is bonded in a bent 150 degrees geometry to two equivalent Si(1,2) atoms. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(1,2) atoms. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.113
_cell_length_b   8.156
_cell_length_c   8.129
_cell_angle_alpha   90.000
_cell_angle_beta   92.957
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   338.527
_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  0.032  0.229  0.873  1.0
  Si  Si1  1  0.020  0.080  0.230  1.0
  Si  Si2  1  0.532  0.227  0.373  1.0
  Si  Si3  1  0.443  0.580  0.224  1.0
  Si  Si4  1  0.432  0.729  0.581  1.0
  Si  Si5  1  0.932  0.727  0.081  1.0
  Si  Si6  1  0.520  0.377  0.730  1.0
  Si  Si7  1  0.943  0.877  0.724  1.0
  O  O8  1  0.820  0.150  0.359  1.0
  O  O9  1  0.148  0.595  0.145  1.0
  O  O10  1  0.005  0.066  0.761  1.0
  O  O11  1  0.815  0.361  0.809  1.0
  O  O12  1  0.315  0.095  0.309  1.0
  O  O13  1  0.505  0.390  0.261  1.0
  O  O14  1  0.476  0.685  0.392  1.0
  O  O15  1  0.648  0.861  0.645  1.0
  O  O16  1  0.144  0.806  0.595  1.0
  O  O17  1  0.320  0.306  0.859  1.0
  O  O18  1  0.487  0.272  0.562  1.0
  O  O19  1  0.976  0.772  0.892  1.0
  O  O20  1  0.459  0.566  0.693  1.0
  O  O21  1  0.959  0.890  0.193  1.0
  O  O22  1  0.644  0.650  0.095  1.0
  O  O23  1  0.987  0.185  0.062  1.0
[/CIF]
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The structure described by SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic P2_1/c space group. Si(1,2) 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 150 degrees geometry to two equivalent Si(1,2) atoms. In the second O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(1,2) atoms. In the third O site, O(3) is bonded in a bent 150 degrees geometry to two equivalent Si(1,2) atoms. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(1,2) atoms. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.113
_cell_length_b   8.156
_cell_length_c   8.129
_cell_angle_alpha   90.000
_cell_angle_beta   92.957
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   338.527
_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  0.032  0.229  0.873  1.0
  Si  Si1  1  0.020  0.080  0.230  1.0
  Si  Si2  1  0.532  0.227  0.373  1.0
  Si  Si3  1  0.443  0.580  0.224  1.0
  Si  Si4  1  0.432  0.729  0.581  1.0
  Si  Si5  1  0.932  0.727  0.081  1.0
  Si  Si6  1  0.520  0.377  0.730  1.0
  Si  Si7  1  0.943  0.877  0.724  1.0
  O  O8  1  0.820  0.150  0.359  1.0
  O  O9  1  0.148  0.595  0.145  1.0
  O  O10  1  0.005  0.066  0.761  1.0
  O  O11  1  0.815  0.361  0.809  1.0
  O  O12  1  0.315  0.095  0.309  1.0
  O  O13  1  0.505  0.390  0.261  1.0
  O  O14  1  0.476  0.685  0.392  1.0
  O  O15  1  0.648  0.861  0.645  1.0
  O  O16  1  0.144  0.806  0.595  1.0
  O  O17  1  0.320  0.306  0.859  1.0
  O  O18  1  0.487  0.272  0.562  1.0
  O  O19  1  0.976  0.772  0.892  1.0
  O  O20  1  0.459  0.566  0.693  1.0
  O  O21  1  0.959  0.890  0.193  1.0
  O  O22  1  0.644  0.650  0.095  1.0
  O  O23  1  0.987  0.185  0.062  1.0
[/CIF]
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