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: 13
;
_database_code_amcsd 0007878
_chemical_formula_sum 'Si O2'
_cell_length_a 6.6211
_cell_length_b 7.9963
_cell_length_c 5.4115
_cell_angle_alpha 90
_cell_angle_beta 100.2277
_cell_angle_gamma 90
_cell_volume 281.955
_exptl_crystal_density_diffrn      2.831
_symmetry_space_group_name_H-M 'C 1 2 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  '-x,y,-z'
  '1/2-x,1/2+y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Si1   0.19117   0.50000   0.28369
Si2   0.24400   0.12610   0.20584
O1   0.31674   0.51016   0.57183
O2   0.13270   0.30628   0.22617
O3   0.32872   0.55266   0.07655
O4   0.00574   0.62869   0.74487