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: 11 ; _database_code_amcsd 0007876 _chemical_formula_sum 'Si O2' _cell_length_a 6.9979 _cell_length_b 8.2122 _cell_length_c 6.5106 _cell_angle_alpha 90 _cell_angle_beta 114.9303 _cell_angle_gamma 90 _cell_volume 339.289 _exptl_crystal_density_diffrn 2.353 _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 0.20423 0.00000 0.21347 Si2 0.39511 0.81983 0.64098 O1 0.50000 0.71754 0.50000 O2 0.00000 0.93053 0.00000 O3 0.79134 0.92676 0.55053 O4 0.41950 0.94158 0.19267 O5 0.80752 0.19767 0.77866