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A reproducible, scaleable synthesis of ZSM-10 is reported. This synthesis is dependent on the presence of 1,4-dimethyl-DABCO cations during the nucleation/aging stage, but this directing agent is not incorporated in the final product. Analysis of the zeolite product during aging shows that offretite is formed first and then converts to ZSM-10. The framework topology of ZSM-10 (K24Al24Si84O216 · xH2O · yR) has been determined from synchrotron X-ray and electron diffraction data, model building, and X-ray powder pattern simulation. ZSM-10 has a large hexagonal unit cell with a = 31.575(7) A, c = 7.525(4) A, P6/mmm maximum topological symmetry, and a tetrahedral framework density of 16.6 T/1,000 A3. The tetrahedral framework is constructed from columns of alternating cancrinite cages and double 6-rings which also build the LTL (Linde Type L or zeolite L) and OFF (offretite) frameworks. Two different one-dimensional, 12-ring pore systems parallel the caxis in ZSM-10. One 12-ring channel is topologically identical to the undulating channel in the LTL framework, and the other is identical to the 12-ring channel in the OFF framework. ZSM-10 appears to be the first zeolite with two distinct, parallel, 12-ring channel systems that occur individually in other zeolites. |
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