Journal of Physical Chemistry B, Vol.106, No.22, 5673-5678, 2002
Framework determination of a polytype of zeolite beta by using electron crystallography
During a trial of synthesizing pure silica zeolite beta, we found recently ITQ-14 was a multiphase crystal and contained small peculiar pillars overgrown on ordinary beta zeolite. We have developed a new method applicable for solving a structure of this kind, i.e., Fourier reconstruction of high resolution transmission electron microscopy (HRTEM) images and enhancement of the atomic positions in blurred potential map obtained by the reconstruction with a support of Patterson map derived from selected area electron diffraction (SAED) patterns, which contain structural information with much higher resolution than that of HRTEM images. The new framework solution obtained by this method turned out to be a structure type C of beta, which was hypothetically proposed by Newsam et al., and we reported it briefly with observation results of surface structure of the framework. In the present paper, basic idea and the determination process are fully discussed.