SiO2 Boisen M B, Gibbs G V, Bukowinski M S T Physics and Chemistry of Minerals 21 (1994) 269-284 Framework silica structures generated using simulated annealing with a potential energy function based on an H6Si2O7 molecule Sample: 9 _database_code_amcsd 0007874 11.1032 7.8989 4.9771 90 112.2654 90 C2/c atom x y z Si .64566 .60868 .83039 O1 0 .81716 .25 O2 .83439 .94282 .46534 O3 .25001 .75 .5