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: 12 _database_code_amcsd 0007877 6.8513 7.3761 6.7085 90 101.9184 90 C2 atom x y z Si1 .01054 0 .23495 Si2 .31067 .87196 .57810 O1 0 .45864 .5 O2 0 .94815 0 O3 .12803 .18858 .29236 O4 .13432 .84126 .37777 O5 .21492 .01077 .72051