Zeolites zero-dimensional

The problem of accessibility in microporous solids is extreme in zero-dimensional zeolite structures such as clathrasils, that is, zeolite-related materials consisting of window-connected cages. The pore openings in these caged structures are restricted to six-membered rings of [Si04] units at most, which corresponds to pore diameters of approximately 0.2 nm [58]. These pores are too small for the removal of templates and, afterward, are impenetrable to typical sorptive molecules for characterization such as N2 and Ar or reactants such as hydrocarbons. Therefore, the intrinsic... 

Figure 19 Crystal structure of the ACO zeolite (a) and its corresponding topology (b) showing connectivity of tetrahedral atoms that could be constructed from periodic double 4-ring (D4R) as the zero-dimensional periodic building unit (PerBU), in bold.

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