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: 12 ; _database_code_amcsd 0007877 _chemical_formula_sum 'Si O2' _cell_length_a 6.8513 _cell_length_b 7.3761 _cell_length_c 6.7085 _cell_angle_alpha 90 _cell_angle_beta 101.9184 _cell_angle_gamma 90 _cell_volume 331.712 _exptl_crystal_density_diffrn 2.406 _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 0.01054 0.00000 0.23495 Si2 0.31067 0.87196 0.57810 O1 0.00000 0.45864 0.50000 O2 0.00000 0.94815 0.00000 O3 0.12803 0.18858 0.29236 O4 0.13432 0.84126 0.37777 O5 0.21492 0.01077 0.72051