Si111.6 O224 (H2 O)22.7

H_45.4O_246.7Si_111.6

Koyama, Y.Ikeda, T.Tatsumi, T.Kubota, Y.

Angew. Chem. Int. ed. (2008) 47, 1042-1046

a=18.2222Å   b=18.2222Å   c=20.0201Å

α=90°   β=90°   γ=90°