The structure described by SiO2 is quartz (beta)-like structured and crystallizes in the monoclinic Pc space group. There are four inequivalent Si sites. In the first Si site, Si(1,8) is bonded to one O(10); one O(14); one O(2,16); and one O(4) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2,5) is bonded to one O(11), one O(14), one O(3), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3,4) is bonded to one O(12), one O(5), one O(7), and one O(9) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(6,7) is bonded to one O(13), one O(15), one O(3), and one O(6) atom to form corner-sharing SiO4 tetrahedra. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1,8) and one Si(2,5) atom. In the second O site, O(2,16) is bonded in a bent 150 degrees geometry to one Si(2,5) and one Si(6,7) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(2,5) and one Si(6,7) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(1,8) atoms. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to two equivalent Si(3,4) atoms. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Si(6,7) atoms. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(3,4) atoms. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to two equivalent Si(2,5) atoms. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Si(3,4) and one Si(6,7) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to two equivalent Si(1,8) atoms. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to two equivalent Si(2,5) atoms. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(1,8) and one Si(3,4) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Si(3,4) and one Si(6,7) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Si(1,8) and one Si(2,5) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to two equivalent Si(6,7) atoms. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.685
_cell_length_b   6.685
_cell_length_c   8.823
_cell_angle_alpha   90.001
_cell_angle_beta   90.001
_cell_angle_gamma   78.683
_symmetry_Int_Tables_number   1
_cell_volume   386.666
_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
  O  O0  1  0.917  0.417  0.559  1.0
  O  O1  1  0.657  0.576  0.770  1.0
  O  O2  1  0.897  0.816  0.270  1.0
  O  O3  1  0.521  0.490  0.502  1.0
  O  O4  1  0.984  0.952  0.003  1.0
  O  O5  1  0.316  0.397  0.270  1.0
  O  O6  1  0.452  0.484  0.003  1.0
  O  O7  1  0.260  0.180  0.032  1.0
  O  O8  1  0.990  0.021  0.502  1.0
  O  O9  1  0.343  0.843  0.870  1.0
  O  O10  1  0.294  0.214  0.532  1.0
  O  O11  1  0.076  0.157  0.770  1.0
  O  O12  1  0.057  0.557  0.059  1.0
  O  O13  1  0.630  0.130  0.371  1.0
  O  O14  1  0.714  0.794  0.532  1.0
  O  O15  1  0.680  0.760  0.032  1.0
  Si  Si16  1  0.807  0.940  0.419  1.0
  Si  Si17  1  0.440  0.307  0.419  1.0
  Si  Si18  1  0.533  0.667  0.919  1.0
  Si  Si19  1  0.905  0.772  0.091  1.0
  Si  Si20  1  0.069  0.202  0.591  1.0
  Si  Si21  1  0.167  0.033  0.919  1.0
  Si  Si22  1  0.702  0.569  0.591  1.0
  Si  Si23  1  0.272  0.405  0.091  1.0
[/CIF]
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The structure described by SiO2 is quartz (beta)-like structured and crystallizes in the monoclinic Pc space group. There are four inequivalent Si sites. In the first Si site, Si(1,8) is bonded to one O(10); one O(14); one O(2,16); and one O(4) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2,5) is bonded to one O(11), one O(14), one O(3), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3,4) is bonded to one O(12), one O(5), one O(7), and one O(9) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(6,7) is bonded to one O(13), one O(15), one O(3), and one O(6) atom to form corner-sharing SiO4 tetrahedra. There are fifteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1,8) and one Si(2,5) atom. In the second O site, O(2,16) is bonded in a bent 150 degrees geometry to one Si(2,5) and one Si(6,7) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(2,5) and one Si(6,7) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(1,8) atoms. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to two equivalent Si(3,4) atoms. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Si(6,7) atoms. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(3,4) atoms. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to two equivalent Si(2,5) atoms. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Si(3,4) and one Si(6,7) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to two equivalent Si(1,8) atoms. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to two equivalent Si(2,5) atoms. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Si(1,8) and one Si(3,4) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Si(3,4) and one Si(6,7) atom. In the fourteenth O site, O(14) is bonded in a bent 150 degrees geometry to one Si(1,8) and one Si(2,5) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to two equivalent Si(6,7) atoms. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.685
_cell_length_b   6.685
_cell_length_c   8.823
_cell_angle_alpha   90.001
_cell_angle_beta   90.001
_cell_angle_gamma   78.683
_symmetry_Int_Tables_number   1
_cell_volume   386.666
_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
  O  O0  1  0.917  0.417  0.559  1.0
  O  O1  1  0.657  0.576  0.770  1.0
  O  O2  1  0.897  0.816  0.270  1.0
  O  O3  1  0.521  0.490  0.502  1.0
  O  O4  1  0.984  0.952  0.003  1.0
  O  O5  1  0.316  0.397  0.270  1.0
  O  O6  1  0.452  0.484  0.003  1.0
  O  O7  1  0.260  0.180  0.032  1.0
  O  O8  1  0.990  0.021  0.502  1.0
  O  O9  1  0.343  0.843  0.870  1.0
  O  O10  1  0.294  0.214  0.532  1.0
  O  O11  1  0.076  0.157  0.770  1.0
  O  O12  1  0.057  0.557  0.059  1.0
  O  O13  1  0.630  0.130  0.371  1.0
  O  O14  1  0.714  0.794  0.532  1.0
  O  O15  1  0.680  0.760  0.032  1.0
  Si  Si16  1  0.807  0.940  0.419  1.0
  Si  Si17  1  0.440  0.307  0.419  1.0
  Si  Si18  1  0.533  0.667  0.919  1.0
  Si  Si19  1  0.905  0.772  0.091  1.0
  Si  Si20  1  0.069  0.202  0.591  1.0
  Si  Si21  1  0.167  0.033  0.919  1.0
  Si  Si22  1  0.702  0.569  0.591  1.0
  Si  Si23  1  0.272  0.405  0.091  1.0
[/CIF]
.