The compound described by SiO2 is High (Orthorhombic) Tridymite structured and crystallizes in the monoclinic Cc space group. There are two 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(4) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing SiO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.014
_cell_length_b   5.014
_cell_length_c   8.320
_cell_angle_alpha   89.172
_cell_angle_beta   89.172
_cell_angle_gamma   119.596
_symmetry_Int_Tables_number   1
_cell_volume   181.815
_cell_formula_units_Z   4
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  0.370  0.779  0.288  1.0
  Si  Si1  1  0.708  0.446  0.163  1.0
  Si  Si2  1  0.779  0.370  0.788  1.0
  Si  Si3  1  0.446  0.708  0.663  1.0
  O  O4  1  0.790  0.446  0.975  1.0
  O  O5  1  0.686  0.585  0.686  1.0
  O  O6  1  0.114  0.440  0.725  1.0
  O  O7  1  0.446  0.790  0.475  1.0
  O  O8  1  0.440  0.114  0.225  1.0
  O  O9  1  0.011  0.540  0.265  1.0
  O  O10  1  0.585  0.686  0.186  1.0
  O  O11  1  0.540  0.011  0.765  1.0
[/CIF]
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The compound described by SiO2 is High (Orthorhombic) Tridymite structured and crystallizes in the monoclinic Cc space group. There are two 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(4) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing SiO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. is represented by the CIF card [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.014
_cell_length_b   5.014
_cell_length_c   8.320
_cell_angle_alpha   89.172
_cell_angle_beta   89.172
_cell_angle_gamma   119.596
_symmetry_Int_Tables_number   1
_cell_volume   181.815
_cell_formula_units_Z   4
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  0.370  0.779  0.288  1.0
  Si  Si1  1  0.708  0.446  0.163  1.0
  Si  Si2  1  0.779  0.370  0.788  1.0
  Si  Si3  1  0.446  0.708  0.663  1.0
  O  O4  1  0.790  0.446  0.975  1.0
  O  O5  1  0.686  0.585  0.686  1.0
  O  O6  1  0.114  0.440  0.725  1.0
  O  O7  1  0.446  0.790  0.475  1.0
  O  O8  1  0.440  0.114  0.225  1.0
  O  O9  1  0.011  0.540  0.265  1.0
  O  O10  1  0.585  0.686  0.186  1.0
  O  O11  1  0.540  0.011  0.765  1.0
[/CIF]
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