An open-framework silicogermanate regularly constructed from natrolite zeolite chains and Ge9O18(OH)4 clusters.

Here we describe the synthesis and structure of PST-18, a novel open-framework silicogermanate with Si/Ge ∼ 0.6, which contains a three-dimensional pore system consisting of large cuboid-shaped cavities with 8-ring windows, as well as with 7-rings interrupted by one OH group. Synchrotron single-crystal X-ray diffraction reveals that the structure of PST-18, synthesized using only tetramethylammonium fluoride as a structure-directing agent, is built up of natrolite zeolite chains and Ge9O18(OH)4 clusters in a fully ordered manner. The discovery of such a hybrid structure of zeolitic building units and non-zeolitic oxide clusters provides a new direction for expanding the structural regime of inorganic microporous crystalline materials.