The structure described by SiO2 crystallizes in the monoclinic C2/m space group. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), and two equivalent O(10) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(5), one O(6), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to two equivalent O(2) and two equivalent O(8) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to two equivalent O(7) and two equivalent O(9) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. In the fifth Si site, Si(5) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in an L-shaped geometry to two equivalent Si(3) atoms. In the third O site, O(3) is bonded in a bent 120 degrees geometry to two equivalent Si(5) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(5) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(5) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Si(4) and one Si(5) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the ninth O site, O(9) is bonded in an L-shaped geometry to two equivalent Si(4) atoms. In the tenth O site, O(10) is bonded in an L-shaped 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   13.485
_cell_length_b   13.485
_cell_length_c   5.452
_cell_angle_alpha   84.740
_cell_angle_beta   84.740
_cell_angle_gamma   88.338
_symmetry_Int_Tables_number   1
_cell_volume   982.791
_cell_formula_units_Z   16
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  0.057  0.441  0.421  1.0
  Si  Si1  1  0.246  0.397  0.140  1.0
  Si  Si2  1  0.442  0.442  0.959  1.0
  Si  Si3  1  0.559  0.943  0.579  1.0
  Si  Si4  1  0.397  0.246  0.140  1.0
  Si  Si5  1  0.603  0.754  0.860  1.0
  Si  Si6  1  0.059  0.059  0.036  1.0
  Si  Si7  1  0.251  0.100  0.209  1.0
  Si  Si8  1  0.943  0.559  0.579  1.0
  Si  Si9  1  0.749  0.900  0.791  1.0
  Si  Si10  1  0.558  0.558  0.041  1.0
  Si  Si11  1  0.754  0.603  0.860  1.0
  Si  Si12  1  0.441  0.057  0.421  1.0
  Si  Si13  1  0.900  0.749  0.791  1.0
  Si  Si14  1  0.100  0.251  0.209  1.0
  Si  Si15  1  0.941  0.941  0.964  1.0
  O  O16  1  0.174  0.463  0.325  1.0
  O  O17  1  0.482  0.482  0.218  1.0
  O  O18  1  0.174  0.174  0.367  1.0
  O  O19  1  0.034  0.323  0.390  1.0
  O  O20  1  0.826  0.537  0.675  1.0
  O  O21  1  0.323  0.323  0.295  1.0
  O  O22  1  0.463  0.174  0.325  1.0
  O  O23  1  0.326  0.170  0.014  1.0
  O  O24  1  0.034  0.178  0.065  1.0
  O  O25  1  0.323  0.034  0.390  1.0
  O  O26  1  0.536  0.679  0.060  1.0
  O  O27  1  0.518  0.518  0.782  1.0
  O  O28  1  0.464  0.321  0.940  1.0
  O  O29  1  0.019  0.019  0.783  1.0
  O  O30  1  0.830  0.674  0.986  1.0
  O  O31  1  0.976  0.524  0.297  1.0
  O  O32  1  0.966  0.822  0.935  1.0
  O  O33  1  0.178  0.034  0.065  1.0
  O  O34  1  0.476  0.024  0.703  1.0
  O  O35  1  0.674  0.830  0.986  1.0
  O  O36  1  0.537  0.826  0.675  1.0
  O  O37  1  0.679  0.536  0.060  1.0
  O  O38  1  0.321  0.464  0.940  1.0
  O  O39  1  0.677  0.677  0.705  1.0
  O  O40  1  0.524  0.976  0.297  1.0
  O  O41  1  0.966  0.677  0.610  1.0
  O  O42  1  0.024  0.476  0.703  1.0
  O  O43  1  0.822  0.966  0.935  1.0
  O  O44  1  0.170  0.326  0.014  1.0
  O  O45  1  0.826  0.826  0.633  1.0
  O  O46  1  0.677  0.966  0.610  1.0
  O  O47  1  0.981  0.981  0.217  1.0
[/CIF]
.
The structure described by SiO2 crystallizes in the monoclinic C2/m space group. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), and two equivalent O(10) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(5), one O(6), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to two equivalent O(2) and two equivalent O(8) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to two equivalent O(7) and two equivalent O(9) atoms to form a mixture of edge and corner-sharing SiO4 tetrahedra. In the fifth Si site, Si(5) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in an L-shaped geometry to two equivalent Si(3) atoms. In the third O site, O(3) is bonded in a bent 120 degrees geometry to two equivalent Si(5) atoms. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(5) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to two equivalent Si(2) atoms. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(5) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Si(4) and one Si(5) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the ninth O site, O(9) is bonded in an L-shaped geometry to two equivalent Si(4) atoms. In the tenth O site, O(10) is bonded in an L-shaped 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   13.485
_cell_length_b   13.485
_cell_length_c   5.452
_cell_angle_alpha   84.740
_cell_angle_beta   84.740
_cell_angle_gamma   88.338
_symmetry_Int_Tables_number   1
_cell_volume   982.791
_cell_formula_units_Z   16
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  0.057  0.441  0.421  1.0
  Si  Si1  1  0.246  0.397  0.140  1.0
  Si  Si2  1  0.442  0.442  0.959  1.0
  Si  Si3  1  0.559  0.943  0.579  1.0
  Si  Si4  1  0.397  0.246  0.140  1.0
  Si  Si5  1  0.603  0.754  0.860  1.0
  Si  Si6  1  0.059  0.059  0.036  1.0
  Si  Si7  1  0.251  0.100  0.209  1.0
  Si  Si8  1  0.943  0.559  0.579  1.0
  Si  Si9  1  0.749  0.900  0.791  1.0
  Si  Si10  1  0.558  0.558  0.041  1.0
  Si  Si11  1  0.754  0.603  0.860  1.0
  Si  Si12  1  0.441  0.057  0.421  1.0
  Si  Si13  1  0.900  0.749  0.791  1.0
  Si  Si14  1  0.100  0.251  0.209  1.0
  Si  Si15  1  0.941  0.941  0.964  1.0
  O  O16  1  0.174  0.463  0.325  1.0
  O  O17  1  0.482  0.482  0.218  1.0
  O  O18  1  0.174  0.174  0.367  1.0
  O  O19  1  0.034  0.323  0.390  1.0
  O  O20  1  0.826  0.537  0.675  1.0
  O  O21  1  0.323  0.323  0.295  1.0
  O  O22  1  0.463  0.174  0.325  1.0
  O  O23  1  0.326  0.170  0.014  1.0
  O  O24  1  0.034  0.178  0.065  1.0
  O  O25  1  0.323  0.034  0.390  1.0
  O  O26  1  0.536  0.679  0.060  1.0
  O  O27  1  0.518  0.518  0.782  1.0
  O  O28  1  0.464  0.321  0.940  1.0
  O  O29  1  0.019  0.019  0.783  1.0
  O  O30  1  0.830  0.674  0.986  1.0
  O  O31  1  0.976  0.524  0.297  1.0
  O  O32  1  0.966  0.822  0.935  1.0
  O  O33  1  0.178  0.034  0.065  1.0
  O  O34  1  0.476  0.024  0.703  1.0
  O  O35  1  0.674  0.830  0.986  1.0
  O  O36  1  0.537  0.826  0.675  1.0
  O  O37  1  0.679  0.536  0.060  1.0
  O  O38  1  0.321  0.464  0.940  1.0
  O  O39  1  0.677  0.677  0.705  1.0
  O  O40  1  0.524  0.976  0.297  1.0
  O  O41  1  0.966  0.677  0.610  1.0
  O  O42  1  0.024  0.476  0.703  1.0
  O  O43  1  0.822  0.966  0.935  1.0
  O  O44  1  0.170  0.326  0.014  1.0
  O  O45  1  0.826  0.826  0.633  1.0
  O  O46  1  0.677  0.966  0.610  1.0
  O  O47  1  0.981  0.981  0.217  1.0
[/CIF]
.