The crystal structure described by SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic P2/c space group. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(10), one O(5), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to two equivalent O(3) and two equivalent O(5) atoms to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the fifth Si site, Si(5) is bonded to one O(1), one O(2), one O(7), and one O(9) atom to form corner-sharing SiO4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(9) is bonded in a linear geometry to two equivalent Si(5) atoms. In the second O site, O(10) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the third O site, O(1) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(5) atom. In the fourth O site, O(2) is bonded in a linear geometry to one Si(4) and one Si(5) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the sixth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the eighth O site, O(6) is bonded in a linear geometry to one Si(1) and one Si(4) atom. In the ninth O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(5) atom. In the tenth O site, O(8) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.400
_cell_length_b   8.761
_cell_length_c   15.775
_cell_angle_alpha   90.000
_cell_angle_beta   91.153
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1022.471
_cell_formula_units_Z   18
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  0.352  0.656  0.080  1.0
  Si  Si1  1  0.148  0.656  0.420  1.0
  Si  Si2  1  0.390  0.650  0.680  1.0
  Si  Si3  1  0.648  0.344  0.920  1.0
  Si  Si4  1  0.250  0.496  0.250  1.0
  Si  Si5  1  0.110  0.650  0.820  1.0
  Si  Si6  1  0.746  0.603  0.056  1.0
  Si  Si7  1  0.443  0.825  0.509  1.0
  Si  Si8  1  0.943  0.175  0.009  1.0
  Si  Si9  1  0.852  0.344  0.580  1.0
  Si  Si10  1  0.254  0.397  0.944  1.0
  Si  Si11  1  0.890  0.350  0.180  1.0
  Si  Si12  1  0.750  0.504  0.750  1.0
  Si  Si13  1  0.610  0.350  0.320  1.0
  Si  Si14  1  0.057  0.825  0.991  1.0
  Si  Si15  1  0.246  0.397  0.556  1.0
  Si  Si16  1  0.754  0.603  0.444  1.0
  Si  Si17  1  0.557  0.175  0.491  1.0
  O  O18  1  0.911  0.220  0.107  1.0
  O  O19  1  0.599  0.719  0.471  1.0
  O  O20  1  0.698  0.390  0.825  1.0
  O  O21  1  0.564  0.695  0.077  1.0
  O  O22  1  0.917  0.614  0.776  1.0
  O  O23  1  0.064  0.305  0.577  1.0
  O  O24  1  0.936  0.695  0.423  1.0
  O  O25  1  0.089  0.780  0.893  1.0
  O  O26  1  0.583  0.614  0.724  1.0
  O  O27  1  0.202  0.512  0.479  1.0
  O  O28  1  0.802  0.390  0.675  1.0
  O  O29  1  0.740  0.198  0.547  1.0
  O  O30  1  0.813  0.506  0.138  1.0
  O  O31  1  0.298  0.512  0.021  1.0
  O  O32  1  0.099  0.281  0.971  1.0
  O  O33  1  0.436  0.305  0.923  1.0
  O  O34  1  0.417  0.386  0.276  1.0
  O  O35  1  0.313  0.494  0.638  1.0
  O  O36  1  0.687  0.506  0.362  1.0
  O  O37  1  0.901  0.719  0.029  1.0
  O  O38  1  0.302  0.610  0.175  1.0
  O  O39  1  0.187  0.494  0.862  1.0
  O  O40  1  0.000  0.000  0.000  1.0
  O  O41  1  0.083  0.386  0.224  1.0
  O  O42  1  0.198  0.610  0.325  1.0
  O  O43  1  0.589  0.220  0.393  1.0
  O  O44  1  0.411  0.780  0.607  1.0
  O  O45  1  0.702  0.488  0.979  1.0
  O  O46  1  0.760  0.198  0.953  1.0
  O  O47  1  0.750  0.291  0.250  1.0
  O  O48  1  0.798  0.488  0.521  1.0
  O  O49  1  0.500  0.000  0.500  1.0
  O  O50  1  0.250  0.709  0.750  1.0
  O  O51  1  0.401  0.281  0.529  1.0
  O  O52  1  0.260  0.802  0.453  1.0
  O  O53  1  0.240  0.802  0.047  1.0
[/CIF]
.
The crystal structure described by SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic P2/c space group. There are five inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(10), one O(5), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to two equivalent O(3) and two equivalent O(5) atoms to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the fifth Si site, Si(5) is bonded to one O(1), one O(2), one O(7), and one O(9) atom to form corner-sharing SiO4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(9) is bonded in a linear geometry to two equivalent Si(5) atoms. In the second O site, O(10) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the third O site, O(1) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(5) atom. In the fourth O site, O(2) is bonded in a linear geometry to one Si(4) and one Si(5) atom. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the sixth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the eighth O site, O(6) is bonded in a linear geometry to one Si(1) and one Si(4) atom. In the ninth O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(5) atom. In the tenth O site, O(8) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.400
_cell_length_b   8.761
_cell_length_c   15.775
_cell_angle_alpha   90.000
_cell_angle_beta   91.153
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   1022.471
_cell_formula_units_Z   18
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  0.352  0.656  0.080  1.0
  Si  Si1  1  0.148  0.656  0.420  1.0
  Si  Si2  1  0.390  0.650  0.680  1.0
  Si  Si3  1  0.648  0.344  0.920  1.0
  Si  Si4  1  0.250  0.496  0.250  1.0
  Si  Si5  1  0.110  0.650  0.820  1.0
  Si  Si6  1  0.746  0.603  0.056  1.0
  Si  Si7  1  0.443  0.825  0.509  1.0
  Si  Si8  1  0.943  0.175  0.009  1.0
  Si  Si9  1  0.852  0.344  0.580  1.0
  Si  Si10  1  0.254  0.397  0.944  1.0
  Si  Si11  1  0.890  0.350  0.180  1.0
  Si  Si12  1  0.750  0.504  0.750  1.0
  Si  Si13  1  0.610  0.350  0.320  1.0
  Si  Si14  1  0.057  0.825  0.991  1.0
  Si  Si15  1  0.246  0.397  0.556  1.0
  Si  Si16  1  0.754  0.603  0.444  1.0
  Si  Si17  1  0.557  0.175  0.491  1.0
  O  O18  1  0.911  0.220  0.107  1.0
  O  O19  1  0.599  0.719  0.471  1.0
  O  O20  1  0.698  0.390  0.825  1.0
  O  O21  1  0.564  0.695  0.077  1.0
  O  O22  1  0.917  0.614  0.776  1.0
  O  O23  1  0.064  0.305  0.577  1.0
  O  O24  1  0.936  0.695  0.423  1.0
  O  O25  1  0.089  0.780  0.893  1.0
  O  O26  1  0.583  0.614  0.724  1.0
  O  O27  1  0.202  0.512  0.479  1.0
  O  O28  1  0.802  0.390  0.675  1.0
  O  O29  1  0.740  0.198  0.547  1.0
  O  O30  1  0.813  0.506  0.138  1.0
  O  O31  1  0.298  0.512  0.021  1.0
  O  O32  1  0.099  0.281  0.971  1.0
  O  O33  1  0.436  0.305  0.923  1.0
  O  O34  1  0.417  0.386  0.276  1.0
  O  O35  1  0.313  0.494  0.638  1.0
  O  O36  1  0.687  0.506  0.362  1.0
  O  O37  1  0.901  0.719  0.029  1.0
  O  O38  1  0.302  0.610  0.175  1.0
  O  O39  1  0.187  0.494  0.862  1.0
  O  O40  1  0.000  0.000  0.000  1.0
  O  O41  1  0.083  0.386  0.224  1.0
  O  O42  1  0.198  0.610  0.325  1.0
  O  O43  1  0.589  0.220  0.393  1.0
  O  O44  1  0.411  0.780  0.607  1.0
  O  O45  1  0.702  0.488  0.979  1.0
  O  O46  1  0.760  0.198  0.953  1.0
  O  O47  1  0.750  0.291  0.250  1.0
  O  O48  1  0.798  0.488  0.521  1.0
  O  O49  1  0.500  0.000  0.500  1.0
  O  O50  1  0.250  0.709  0.750  1.0
  O  O51  1  0.401  0.281  0.529  1.0
  O  O52  1  0.260  0.802  0.453  1.0
  O  O53  1  0.240  0.802  0.047  1.0
[/CIF]
.