The material described by SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic C2/m space group. The structure consists of four water atoms inside a Si8O15 framework. In the Si8O15 framework, there are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(5), one O(7), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded in a trigonal non-coplanar geometry to one O(5), one O(6), and one O(7) atom. In the third Si site, Si(3) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(1), one O(2), one O(8), and one O(9) atom to form corner-sharing SiO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the fourth O site, O(4) is bonded in a linear geometry to two equivalent Si(3) atoms. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to two equivalent Si(4) atoms. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.489
_cell_length_b   11.489
_cell_length_c   10.077
_cell_angle_alpha   87.183
_cell_angle_beta   87.183
_cell_angle_gamma   132.380
_symmetry_Int_Tables_number   1
_cell_volume   975.363
_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  0.011  0.477  0.220  1.0
  Si  Si1  1  0.969  0.287  0.985  1.0
  Si  Si2  1  0.319  0.472  0.888  1.0
  Si  Si3  1  0.329  0.673  0.345  1.0
  Si  Si4  1  0.327  0.671  0.655  1.0
  Si  Si5  1  0.528  0.681  0.112  1.0
  Si  Si6  1  0.287  0.969  0.985  1.0
  Si  Si7  1  0.477  0.011  0.220  1.0
  Si  Si8  1  0.523  0.989  0.780  1.0
  Si  Si9  1  0.713  0.031  0.015  1.0
  Si  Si10  1  0.472  0.319  0.888  1.0
  Si  Si11  1  0.673  0.329  0.345  1.0
  Si  Si12  1  0.671  0.327  0.655  1.0
  Si  Si13  1  0.681  0.528  0.112  1.0
  Si  Si14  1  0.031  0.713  0.015  1.0
  Si  Si15  1  0.989  0.523  0.780  1.0
  O  O16  1  0.657  0.436  0.251  1.0
  O  O17  1  0.845  0.385  0.312  1.0
  O  O18  1  0.436  0.657  0.251  1.0
  O  O19  1  0.385  0.845  0.312  1.0
  O  O20  1  0.597  0.403  0.000  1.0
  O  O21  1  0.597  0.597  0.133  1.0
  O  O22  1  0.356  0.999  0.130  1.0
  O  O23  1  0.675  0.870  0.068  1.0
  O  O24  1  0.999  0.356  0.130  1.0
  O  O25  1  0.870  0.675  0.068  1.0
  O  O26  1  0.623  0.060  0.120  1.0
  O  O27  1  0.539  0.144  0.321  1.0
  O  O28  1  0.060  0.623  0.120  1.0
  O  O29  1  0.651  0.349  0.500  1.0
  O  O30  1  0.869  0.131  0.500  1.0
  O  O31  1  0.144  0.539  0.321  1.0
  O  O32  1  0.856  0.461  0.679  1.0
  O  O33  1  0.131  0.869  0.500  1.0
  O  O34  1  0.349  0.651  0.500  1.0
  O  O35  1  0.940  0.377  0.880  1.0
  O  O36  1  0.461  0.856  0.679  1.0
  O  O37  1  0.377  0.940  0.880  1.0
  O  O38  1  0.130  0.325  0.932  1.0
  O  O39  1  0.001  0.644  0.870  1.0
  O  O40  1  0.325  0.130  0.932  1.0
  O  O41  1  0.644  0.001  0.870  1.0
  O  O42  1  0.403  0.403  0.867  1.0
  O  O43  1  0.403  0.597  0.000  1.0
  O  O44  1  0.615  0.155  0.688  1.0
  O  O45  1  0.564  0.343  0.749  1.0
  O  O46  1  0.155  0.615  0.688  1.0
  O  O47  1  0.343  0.564  0.749  1.0
[/CIF]
.
The material described by SiO2 is Low Tridymite-like structured and crystallizes in the monoclinic C2/m space group. The structure consists of four water atoms inside a Si8O15 framework. In the Si8O15 framework, there are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(5), one O(7), and one O(8) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded in a trigonal non-coplanar geometry to one O(5), one O(6), and one O(7) atom. In the third Si site, Si(3) is bonded to one O(1), one O(3), one O(4), and one O(6) atom to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(1), one O(2), one O(8), and one O(9) atom to form corner-sharing SiO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the fourth O site, O(4) is bonded in a linear geometry to two equivalent Si(3) atoms. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(4) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to two equivalent Si(4) atoms. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   11.489
_cell_length_b   11.489
_cell_length_c   10.077
_cell_angle_alpha   87.183
_cell_angle_beta   87.183
_cell_angle_gamma   132.380
_symmetry_Int_Tables_number   1
_cell_volume   975.363
_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  0.011  0.477  0.220  1.0
  Si  Si1  1  0.969  0.287  0.985  1.0
  Si  Si2  1  0.319  0.472  0.888  1.0
  Si  Si3  1  0.329  0.673  0.345  1.0
  Si  Si4  1  0.327  0.671  0.655  1.0
  Si  Si5  1  0.528  0.681  0.112  1.0
  Si  Si6  1  0.287  0.969  0.985  1.0
  Si  Si7  1  0.477  0.011  0.220  1.0
  Si  Si8  1  0.523  0.989  0.780  1.0
  Si  Si9  1  0.713  0.031  0.015  1.0
  Si  Si10  1  0.472  0.319  0.888  1.0
  Si  Si11  1  0.673  0.329  0.345  1.0
  Si  Si12  1  0.671  0.327  0.655  1.0
  Si  Si13  1  0.681  0.528  0.112  1.0
  Si  Si14  1  0.031  0.713  0.015  1.0
  Si  Si15  1  0.989  0.523  0.780  1.0
  O  O16  1  0.657  0.436  0.251  1.0
  O  O17  1  0.845  0.385  0.312  1.0
  O  O18  1  0.436  0.657  0.251  1.0
  O  O19  1  0.385  0.845  0.312  1.0
  O  O20  1  0.597  0.403  0.000  1.0
  O  O21  1  0.597  0.597  0.133  1.0
  O  O22  1  0.356  0.999  0.130  1.0
  O  O23  1  0.675  0.870  0.068  1.0
  O  O24  1  0.999  0.356  0.130  1.0
  O  O25  1  0.870  0.675  0.068  1.0
  O  O26  1  0.623  0.060  0.120  1.0
  O  O27  1  0.539  0.144  0.321  1.0
  O  O28  1  0.060  0.623  0.120  1.0
  O  O29  1  0.651  0.349  0.500  1.0
  O  O30  1  0.869  0.131  0.500  1.0
  O  O31  1  0.144  0.539  0.321  1.0
  O  O32  1  0.856  0.461  0.679  1.0
  O  O33  1  0.131  0.869  0.500  1.0
  O  O34  1  0.349  0.651  0.500  1.0
  O  O35  1  0.940  0.377  0.880  1.0
  O  O36  1  0.461  0.856  0.679  1.0
  O  O37  1  0.377  0.940  0.880  1.0
  O  O38  1  0.130  0.325  0.932  1.0
  O  O39  1  0.001  0.644  0.870  1.0
  O  O40  1  0.325  0.130  0.932  1.0
  O  O41  1  0.644  0.001  0.870  1.0
  O  O42  1  0.403  0.403  0.867  1.0
  O  O43  1  0.403  0.597  0.000  1.0
  O  O44  1  0.615  0.155  0.688  1.0
  O  O45  1  0.564  0.343  0.749  1.0
  O  O46  1  0.155  0.615  0.688  1.0
  O  O47  1  0.343  0.564  0.749  1.0
[/CIF]
.