Proposed synthetic zeolite ECR-1 structure gives a new zeolite framework topology

Abstract

Zeolites dominate petroleum and new petrochemical processing, and any new large-pore zeolite is of major significance. Here we propose a structure for the recently synthesized zeolite phase ECR-1 (ref. 1). The proposed model is an intimate twin of the mordenite² and mazzite³ structures, constructed by interposing layers of mordenite-like sheets between layers of mazzite-like cages. Although there is an ambiguity between two ways the layers are interconnected, this layer-twin model explains the results of sorption and crystallization experiments, the spectroscopic data, X-ray and electron diffraction, and high-resolution transmission electron microscopy (HRTEM) lattice imaging results. The ECR-1 channel system is one-dimensional, with 12-membered-ring openings intermediate in size between those of the parent materials. The structure solution confirms the power of HRTEM lattice imaging in helping to solve the structures of microcrystalline materials^4,5, and the intergrowth of ECR-1 and mazzite observed in the images suggests that a new subfamily of zeolite materials based on differing sequences of the two structural layers can be synthesized.