The material 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(1), one O(2), one O(3), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(5), 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(4) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the second O site, O(5) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the third O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the fourth O site, O(7) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(8) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the sixth O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the seventh O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the eighth O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.463
_cell_length_b   9.805
_cell_length_c   9.805
_cell_angle_alpha   88.269
_cell_angle_beta   81.150
_cell_angle_gamma   81.150
_symmetry_Int_Tables_number   1
_cell_volume   700.448
_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  0.916  0.390  0.833  1.0
  Si  Si1  1  0.084  0.167  0.610  1.0
  Si  Si2  1  0.084  0.610  0.167  1.0
  Si  Si3  1  0.916  0.833  0.390  1.0
  Si  Si4  1  0.155  0.619  0.844  1.0
  Si  Si5  1  0.845  0.156  0.381  1.0
  Si  Si6  1  0.845  0.381  0.156  1.0
  Si  Si7  1  0.155  0.844  0.619  1.0
  Si  Si8  1  0.548  0.487  0.715  1.0
  Si  Si9  1  0.452  0.285  0.513  1.0
  Si  Si10  1  0.452  0.513  0.285  1.0
  Si  Si11  1  0.548  0.715  0.487  1.0
  O  O12  1  0.000  0.252  0.748  1.0
  O  O13  1  0.000  0.748  0.252  1.0
  O  O14  1  0.045  0.507  0.790  1.0
  O  O15  1  0.955  0.210  0.493  1.0
  O  O16  1  0.955  0.493  0.210  1.0
  O  O17  1  0.045  0.790  0.507  1.0
  O  O18  1  0.090  0.646  0.005  1.0
  O  O19  1  0.910  0.995  0.354  1.0
  O  O20  1  0.910  0.354  0.995  1.0
  O  O21  1  0.090  0.005  0.646  1.0
  O  O22  1  0.887  0.238  0.238  1.0
  O  O23  1  0.113  0.762  0.762  1.0
  O  O24  1  0.500  0.650  0.350  1.0
  O  O25  1  0.500  0.350  0.650  1.0
  O  O26  1  0.610  0.591  0.591  1.0
  O  O27  1  0.390  0.409  0.409  1.0
  O  O28  1  0.372  0.816  0.562  1.0
  O  O29  1  0.628  0.438  0.184  1.0
  O  O30  1  0.628  0.184  0.438  1.0
  O  O31  1  0.372  0.562  0.816  1.0
  O  O32  1  0.712  0.804  0.446  1.0
  O  O33  1  0.288  0.554  0.196  1.0
  O  O34  1  0.288  0.196  0.554  1.0
  O  O35  1  0.712  0.446  0.804  1.0
[/CIF]
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The material 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(1), one O(2), one O(3), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(5), 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(4) is bonded in a bent 150 degrees geometry to two equivalent Si(2) atoms. In the second O site, O(5) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the third O site, O(6) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the fourth O site, O(7) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the fifth O site, O(8) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. In the sixth O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the seventh O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the eighth O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. is represented by the CIF file [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.463
_cell_length_b   9.805
_cell_length_c   9.805
_cell_angle_alpha   88.269
_cell_angle_beta   81.150
_cell_angle_gamma   81.150
_symmetry_Int_Tables_number   1
_cell_volume   700.448
_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  0.916  0.390  0.833  1.0
  Si  Si1  1  0.084  0.167  0.610  1.0
  Si  Si2  1  0.084  0.610  0.167  1.0
  Si  Si3  1  0.916  0.833  0.390  1.0
  Si  Si4  1  0.155  0.619  0.844  1.0
  Si  Si5  1  0.845  0.156  0.381  1.0
  Si  Si6  1  0.845  0.381  0.156  1.0
  Si  Si7  1  0.155  0.844  0.619  1.0
  Si  Si8  1  0.548  0.487  0.715  1.0
  Si  Si9  1  0.452  0.285  0.513  1.0
  Si  Si10  1  0.452  0.513  0.285  1.0
  Si  Si11  1  0.548  0.715  0.487  1.0
  O  O12  1  0.000  0.252  0.748  1.0
  O  O13  1  0.000  0.748  0.252  1.0
  O  O14  1  0.045  0.507  0.790  1.0
  O  O15  1  0.955  0.210  0.493  1.0
  O  O16  1  0.955  0.493  0.210  1.0
  O  O17  1  0.045  0.790  0.507  1.0
  O  O18  1  0.090  0.646  0.005  1.0
  O  O19  1  0.910  0.995  0.354  1.0
  O  O20  1  0.910  0.354  0.995  1.0
  O  O21  1  0.090  0.005  0.646  1.0
  O  O22  1  0.887  0.238  0.238  1.0
  O  O23  1  0.113  0.762  0.762  1.0
  O  O24  1  0.500  0.650  0.350  1.0
  O  O25  1  0.500  0.350  0.650  1.0
  O  O26  1  0.610  0.591  0.591  1.0
  O  O27  1  0.390  0.409  0.409  1.0
  O  O28  1  0.372  0.816  0.562  1.0
  O  O29  1  0.628  0.438  0.184  1.0
  O  O30  1  0.628  0.184  0.438  1.0
  O  O31  1  0.372  0.562  0.816  1.0
  O  O32  1  0.712  0.804  0.446  1.0
  O  O33  1  0.288  0.554  0.196  1.0
  O  O34  1  0.288  0.196  0.554  1.0
  O  O35  1  0.712  0.446  0.804  1.0
[/CIF]
.