The structure described by SiO2 is Low Tridymite-like structured and crystallizes in the orthorhombic Cmc2_1 space group. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), and two equivalent O(6) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(2), and two equivalent O(7) atoms to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(3), one O(5), and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(3) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the third O site, O(5) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the fourth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fifth O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the sixth O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(2) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.039
_cell_length_b   11.161
_cell_length_c   11.161
_cell_angle_alpha   102.859
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   611.879
_cell_formula_units_Z   12
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  0.499  0.995  0.416  1.0
  Si  Si1  1  0.999  0.005  0.584  1.0
  Si  Si2  1  0.499  0.584  0.005  1.0
  Si  Si3  1  0.999  0.416  0.995  1.0
  Si  Si4  1  0.912  0.754  0.657  1.0
  Si  Si5  1  0.412  0.246  0.343  1.0
  Si  Si6  1  0.912  0.343  0.246  1.0
  Si  Si7  1  0.412  0.657  0.754  1.0
  Si  Si8  1  0.387  0.726  0.274  1.0
  Si  Si9  1  0.887  0.274  0.726  1.0
  Si  Si10  1  0.888  0.622  0.378  1.0
  Si  Si11  1  0.388  0.378  0.622  1.0
  O  O12  1  0.484  0.108  0.350  1.0
  O  O13  1  0.984  0.892  0.650  1.0
  O  O14  1  0.484  0.650  0.892  1.0
  O  O15  1  0.984  0.350  0.108  1.0
  O  O16  1  0.941  0.663  0.523  1.0
  O  O17  1  0.441  0.337  0.477  1.0
  O  O18  1  0.941  0.477  0.337  1.0
  O  O19  1  0.441  0.523  0.663  1.0
  O  O20  1  0.086  0.695  0.305  1.0
  O  O21  1  0.586  0.305  0.695  1.0
  O  O22  1  0.433  0.871  0.316  1.0
  O  O23  1  0.933  0.129  0.684  1.0
  O  O24  1  0.086  0.347  0.653  1.0
  O  O25  1  0.586  0.653  0.347  1.0
  O  O26  1  0.293  0.470  0.985  1.0
  O  O27  1  0.793  0.530  0.015  1.0
  O  O28  1  0.293  0.015  0.530  1.0
  O  O29  1  0.793  0.985  0.470  1.0
  O  O30  1  0.113  0.707  0.750  1.0
  O  O31  1  0.613  0.293  0.250  1.0
  O  O32  1  0.113  0.250  0.293  1.0
  O  O33  1  0.613  0.750  0.707  1.0
  O  O34  1  0.933  0.316  0.871  1.0
  O  O35  1  0.433  0.684  0.129  1.0
[/CIF]
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The structure described by SiO2 is Low Tridymite-like structured and crystallizes in the orthorhombic Cmc2_1 space group. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(4), and two equivalent O(6) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(2), and two equivalent O(7) atoms to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(3), one O(5), and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(3) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the second O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the third O site, O(5) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the fourth O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fifth O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the sixth O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(2) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.039
_cell_length_b   11.161
_cell_length_c   11.161
_cell_angle_alpha   102.859
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   611.879
_cell_formula_units_Z   12
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  0.499  0.995  0.416  1.0
  Si  Si1  1  0.999  0.005  0.584  1.0
  Si  Si2  1  0.499  0.584  0.005  1.0
  Si  Si3  1  0.999  0.416  0.995  1.0
  Si  Si4  1  0.912  0.754  0.657  1.0
  Si  Si5  1  0.412  0.246  0.343  1.0
  Si  Si6  1  0.912  0.343  0.246  1.0
  Si  Si7  1  0.412  0.657  0.754  1.0
  Si  Si8  1  0.387  0.726  0.274  1.0
  Si  Si9  1  0.887  0.274  0.726  1.0
  Si  Si10  1  0.888  0.622  0.378  1.0
  Si  Si11  1  0.388  0.378  0.622  1.0
  O  O12  1  0.484  0.108  0.350  1.0
  O  O13  1  0.984  0.892  0.650  1.0
  O  O14  1  0.484  0.650  0.892  1.0
  O  O15  1  0.984  0.350  0.108  1.0
  O  O16  1  0.941  0.663  0.523  1.0
  O  O17  1  0.441  0.337  0.477  1.0
  O  O18  1  0.941  0.477  0.337  1.0
  O  O19  1  0.441  0.523  0.663  1.0
  O  O20  1  0.086  0.695  0.305  1.0
  O  O21  1  0.586  0.305  0.695  1.0
  O  O22  1  0.433  0.871  0.316  1.0
  O  O23  1  0.933  0.129  0.684  1.0
  O  O24  1  0.086  0.347  0.653  1.0
  O  O25  1  0.586  0.653  0.347  1.0
  O  O26  1  0.293  0.470  0.985  1.0
  O  O27  1  0.793  0.530  0.015  1.0
  O  O28  1  0.293  0.015  0.530  1.0
  O  O29  1  0.793  0.985  0.470  1.0
  O  O30  1  0.113  0.707  0.750  1.0
  O  O31  1  0.613  0.293  0.250  1.0
  O  O32  1  0.113  0.250  0.293  1.0
  O  O33  1  0.613  0.750  0.707  1.0
  O  O34  1  0.933  0.316  0.871  1.0
  O  O35  1  0.433  0.684  0.129  1.0
[/CIF]
.