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: 23 _database_code_amcsd 0007888 4.1605 4.1294 7.4211 90 101.3752 90 P2 atom x y z Si1 .18244 0 .69651 Si2 .38098 .58564 .17797 O1 .02399 .75200 .18927 O2 .5 .73859 0 O3 .38562 .71473 .64074 O4 0 .15907 .5 O5 .48963 .20196 .18802