The compound described by SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(6), one O(7), and one O(8) atom to form corner-sharing SiO4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the second O site, O(8) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the third O site, O(1) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fourth O site, O(2) is bonded in a linear geometry to two equivalent Si(1) atoms. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the sixth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the eighth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.927
_cell_length_b   9.200
_cell_length_c   9.200
_cell_angle_alpha   111.013
_cell_angle_beta   98.723
_cell_angle_gamma   98.723
_symmetry_Int_Tables_number   1
_cell_volume   679.518
_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  0.105  0.404  0.892  1.0
  Si  Si1  1  0.310  0.997  0.200  1.0
  Si  Si2  1  0.690  0.003  0.800  1.0
  Si  Si3  1  0.895  0.596  0.108  1.0
  Si  Si4  1  0.690  0.800  0.003  1.0
  Si  Si5  1  0.329  0.905  0.702  1.0
  Si  Si6  1  0.105  0.892  0.404  1.0
  Si  Si7  1  0.329  0.702  0.905  1.0
  Si  Si8  1  0.895  0.108  0.596  1.0
  Si  Si9  1  0.671  0.095  0.298  1.0
  Si  Si10  1  0.310  0.200  0.997  1.0
  Si  Si11  1  0.671  0.298  0.095  1.0
  O  O12  1  0.715  0.938  0.179  1.0
  O  O13  1  0.000  0.500  0.000  1.0
  O  O14  1  0.000  0.275  0.725  1.0
  O  O15  1  0.731  0.879  0.879  1.0
  O  O16  1  0.196  0.990  0.317  1.0
  O  O17  1  0.285  0.062  0.821  1.0
  O  O18  1  0.228  0.525  0.854  1.0
  O  O19  1  0.715  0.179  0.938  1.0
  O  O20  1  0.707  0.240  0.240  1.0
  O  O21  1  0.512  0.944  0.700  1.0
  O  O22  1  0.772  0.146  0.475  1.0
  O  O23  1  0.488  0.056  0.300  1.0
  O  O24  1  0.228  0.854  0.525  1.0
  O  O25  1  0.804  0.010  0.683  1.0
  O  O26  1  0.269  0.121  0.121  1.0
  O  O27  1  0.772  0.475  0.146  1.0
  O  O28  1  0.000  0.725  0.275  1.0
  O  O29  1  0.285  0.821  0.062  1.0
  O  O30  1  0.000  0.000  0.500  1.0
  O  O31  1  0.488  0.300  0.056  1.0
  O  O32  1  0.804  0.683  0.010  1.0
  O  O33  1  0.293  0.760  0.760  1.0
  O  O34  1  0.512  0.700  0.944  1.0
  O  O35  1  0.196  0.317  0.990  1.0
[/CIF]
.
The compound described by SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(1), one O(6), one O(7), and one O(8) atom to form corner-sharing SiO4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the second O site, O(8) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the third O site, O(1) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fourth O site, O(2) is bonded in a linear geometry to two equivalent Si(1) atoms. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the sixth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the eighth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.927
_cell_length_b   9.200
_cell_length_c   9.200
_cell_angle_alpha   111.013
_cell_angle_beta   98.723
_cell_angle_gamma   98.723
_symmetry_Int_Tables_number   1
_cell_volume   679.518
_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  0.105  0.404  0.892  1.0
  Si  Si1  1  0.310  0.997  0.200  1.0
  Si  Si2  1  0.690  0.003  0.800  1.0
  Si  Si3  1  0.895  0.596  0.108  1.0
  Si  Si4  1  0.690  0.800  0.003  1.0
  Si  Si5  1  0.329  0.905  0.702  1.0
  Si  Si6  1  0.105  0.892  0.404  1.0
  Si  Si7  1  0.329  0.702  0.905  1.0
  Si  Si8  1  0.895  0.108  0.596  1.0
  Si  Si9  1  0.671  0.095  0.298  1.0
  Si  Si10  1  0.310  0.200  0.997  1.0
  Si  Si11  1  0.671  0.298  0.095  1.0
  O  O12  1  0.715  0.938  0.179  1.0
  O  O13  1  0.000  0.500  0.000  1.0
  O  O14  1  0.000  0.275  0.725  1.0
  O  O15  1  0.731  0.879  0.879  1.0
  O  O16  1  0.196  0.990  0.317  1.0
  O  O17  1  0.285  0.062  0.821  1.0
  O  O18  1  0.228  0.525  0.854  1.0
  O  O19  1  0.715  0.179  0.938  1.0
  O  O20  1  0.707  0.240  0.240  1.0
  O  O21  1  0.512  0.944  0.700  1.0
  O  O22  1  0.772  0.146  0.475  1.0
  O  O23  1  0.488  0.056  0.300  1.0
  O  O24  1  0.228  0.854  0.525  1.0
  O  O25  1  0.804  0.010  0.683  1.0
  O  O26  1  0.269  0.121  0.121  1.0
  O  O27  1  0.772  0.475  0.146  1.0
  O  O28  1  0.000  0.725  0.275  1.0
  O  O29  1  0.285  0.821  0.062  1.0
  O  O30  1  0.000  0.000  0.500  1.0
  O  O31  1  0.488  0.300  0.056  1.0
  O  O32  1  0.804  0.683  0.010  1.0
  O  O33  1  0.293  0.760  0.760  1.0
  O  O34  1  0.512  0.700  0.944  1.0
  O  O35  1  0.196  0.317  0.990  1.0
[/CIF]
.