Abstract
The mixed silicate–water host framework, 3 [{[Si8O18(OH)2]6–}2[H2O]97], of the title compound contains unprecedented and remarkable structural features, e.g. pseudo-hexagonal layer-like subunits with large circular apertures (free diameter ca. 7.9 Å) that resemble layer-like structural units of large-pore zeolite-type materials; the preparation and X-ray structure of the heteronetwork clathrate are reported.