The compound 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(5), and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(4), one O(6), and two equivalent O(1) 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(7) atoms to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(4), one O(6), and two equivalent O(3) atoms to form corner-sharing SiO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. In the second O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the third O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the sixth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.056
_cell_length_b   11.162
_cell_length_c   11.162
_cell_angle_alpha   102.183
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   615.727
_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  0.225  0.995  0.417  1.0
  Si  Si1  1  0.158  0.726  0.274  1.0
  Si  Si2  1  0.725  0.005  0.583  1.0
  Si  Si3  1  0.725  0.344  0.247  1.0
  Si  Si4  1  0.725  0.753  0.656  1.0
  Si  Si5  1  0.225  0.656  0.753  1.0
  Si  Si6  1  0.658  0.274  0.726  1.0
  Si  Si7  1  0.658  0.621  0.379  1.0
  Si  Si8  1  0.225  0.247  0.344  1.0
  Si  Si9  1  0.225  0.583  0.005  1.0
  Si  Si10  1  0.158  0.379  0.621  1.0
  Si  Si11  1  0.725  0.417  0.995  1.0
  O  O12  1  0.706  0.129  0.686  1.0
  O  O13  1  0.021  0.473  0.010  1.0
  O  O14  1  0.706  0.314  0.871  1.0
  O  O15  1  0.206  0.524  0.662  1.0
  O  O16  1  0.359  0.306  0.694  1.0
  O  O17  1  0.706  0.476  0.338  1.0
  O  O18  1  0.157  0.645  0.891  1.0
  O  O19  1  0.657  0.355  0.109  1.0
  O  O20  1  0.706  0.662  0.524  1.0
  O  O21  1  0.359  0.653  0.347  1.0
  O  O22  1  0.521  0.527  0.990  1.0
  O  O23  1  0.859  0.347  0.653  1.0
  O  O24  1  0.019  0.290  0.251  1.0
  O  O25  1  0.206  0.338  0.476  1.0
  O  O26  1  0.859  0.694  0.306  1.0
  O  O27  1  0.657  0.891  0.645  1.0
  O  O28  1  0.521  0.010  0.473  1.0
  O  O29  1  0.519  0.710  0.749  1.0
  O  O30  1  0.157  0.109  0.355  1.0
  O  O31  1  0.206  0.871  0.314  1.0
  O  O32  1  0.019  0.749  0.710  1.0
  O  O33  1  0.021  0.990  0.527  1.0
  O  O34  1  0.519  0.251  0.290  1.0
  O  O35  1  0.206  0.686  0.129  1.0
[/CIF]
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The compound 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(5), and two equivalent O(2) atoms to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(4), one O(6), and two equivalent O(1) 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(7) atoms to form corner-sharing SiO4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(4), one O(6), and two equivalent O(3) atoms to form corner-sharing SiO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. In the second O site, O(7) is bonded in a bent 150 degrees geometry to two equivalent Si(3) atoms. In the third O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fourth O site, O(2) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fifth O site, O(3) is bonded in a bent 150 degrees geometry to one Si(3) and one Si(4) atom. In the sixth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_SiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.056
_cell_length_b   11.162
_cell_length_c   11.162
_cell_angle_alpha   102.183
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   615.727
_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  0.225  0.995  0.417  1.0
  Si  Si1  1  0.158  0.726  0.274  1.0
  Si  Si2  1  0.725  0.005  0.583  1.0
  Si  Si3  1  0.725  0.344  0.247  1.0
  Si  Si4  1  0.725  0.753  0.656  1.0
  Si  Si5  1  0.225  0.656  0.753  1.0
  Si  Si6  1  0.658  0.274  0.726  1.0
  Si  Si7  1  0.658  0.621  0.379  1.0
  Si  Si8  1  0.225  0.247  0.344  1.0
  Si  Si9  1  0.225  0.583  0.005  1.0
  Si  Si10  1  0.158  0.379  0.621  1.0
  Si  Si11  1  0.725  0.417  0.995  1.0
  O  O12  1  0.706  0.129  0.686  1.0
  O  O13  1  0.021  0.473  0.010  1.0
  O  O14  1  0.706  0.314  0.871  1.0
  O  O15  1  0.206  0.524  0.662  1.0
  O  O16  1  0.359  0.306  0.694  1.0
  O  O17  1  0.706  0.476  0.338  1.0
  O  O18  1  0.157  0.645  0.891  1.0
  O  O19  1  0.657  0.355  0.109  1.0
  O  O20  1  0.706  0.662  0.524  1.0
  O  O21  1  0.359  0.653  0.347  1.0
  O  O22  1  0.521  0.527  0.990  1.0
  O  O23  1  0.859  0.347  0.653  1.0
  O  O24  1  0.019  0.290  0.251  1.0
  O  O25  1  0.206  0.338  0.476  1.0
  O  O26  1  0.859  0.694  0.306  1.0
  O  O27  1  0.657  0.891  0.645  1.0
  O  O28  1  0.521  0.010  0.473  1.0
  O  O29  1  0.519  0.710  0.749  1.0
  O  O30  1  0.157  0.109  0.355  1.0
  O  O31  1  0.206  0.871  0.314  1.0
  O  O32  1  0.019  0.749  0.710  1.0
  O  O33  1  0.021  0.990  0.527  1.0
  O  O34  1  0.519  0.251  0.290  1.0
  O  O35  1  0.206  0.686  0.129  1.0
[/CIF]
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