Synthesis and Structure Determination by 3D Electron Diffraction of the Extra-large Pore Zeolite ITQ-70.

In this study, we present the synthesis, characterization, and structural analysis of a novel zeolite, ITQ-70, using 3D electron diffraction. This unique material was synthesized under alkaline conditions, employing tetrakis(diethylamino)phosphonium as an organic structure-directing agent, leading to the formation of a pure silica zeolite. ITQ-70 is distinguished by its extra-large pore apertures, which extend along all three axes and intersect one to the other. A notable feature of this zeolite is the presence of structurally ordered defects in very high concentrations (38 % of the silicon atoms). As a result, ITQ-70 exhibits the lowest framework density (10.0 T/1000 Å) ever reported for any zeolite except RWY (7.6 T/1000 Å), which contains sulfur instead of oxygen connecting T-atoms.