data_global
_amcsd_formula_title 'SiO2'
loop_
_publ_author_name
'Boisen M B'
'Gibbs G V'
'Bukowinski M S T'
_journal_name_full 'Physics and Chemistry of Minerals'
_journal_volume 21 
_journal_year 1994
_journal_page_first 269
_journal_page_last 284
_publ_section_title
;
 Framework silica structures generated using simulated annealing
 with a potential energy function based on an H6Si2O7 molecule
 Sample: 1
;
_database_code_amcsd 0007866
_chemical_formula_sum 'Si O2'
_cell_length_a 8.6557
_cell_length_b 8.6557
_cell_length_c 4.7702
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 357.389
_exptl_crystal_density_diffrn      2.233
_symmetry_space_group_name_H-M 'I -4'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,1/2+z'
  'y,-x,-z'
  '1/2+y,1/2-x,1/2-z'
  '-x,-y,z'
  '1/2-x,1/2-y,1/2+z'
  '-y,x,-z'
  '1/2-y,1/2+x,1/2-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Si   0.17244   0.17581   0.02405
O1   0.28204   0.19187   0.29810
O2   0.69652   0.50674   0.38447