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 Å3) ever reported for any zeolite except RWY (7.6 T/1000 Å3), which contains sulfur instead of oxygen connecting T-atoms.

• Klíčová slova
• 3DED, NMR, chiral, extra-large pore zeolite, structure,
• Publikační typ
• časopisecké články MeSH

Our study compares short-range order parameters refined from the diffuse scattering in single-crystal X-ray and single-crystal electron diffraction data. Nb0.84CoSb was chosen as a reference material. The correlations between neighbouring vacancies and the displacements of Sb and Co atoms were refined from the diffuse scattering using a Monte Carlo refinement in DISCUS. The difference between the Sb and Co displacements refined from the diffuse scattering and the Sb and Co displacements refined from the Bragg reflections in single-crystal X-ray diffraction data is 0.012 (7) Å for the refinement on diffuse scattering in single-crystal X-ray diffraction data and 0.03 (2) Å for the refinement on the diffuse scattering in single-crystal electron diffraction data. As electron diffraction requires much smaller crystals than X-ray diffraction, this opens up the possibility of refining short-range order parameters in many technologically relevant materials for which no crystals large enough for single-crystal X-ray diffraction are available.

• Klíčová slova
• 3D difference pair distribution functions, 3D electron diffraction, 3D-ΔPDF, 3DED, single-crystal diffuse scattering,
• Publikační typ
• časopisecké články MeSH