STRUCTURAL DETERMINATION OF MESOPOROUS MATERIALS BY ELECTRON MICROSCOPY. Osamu Terasaki, Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-77, JAPAN

HREM images of zeolites and related materials( "zeolites" ) give an important clue to solve the structures with diffuse scatterintg which are difficult to be solved from the averaged structural information that diffraction experiment can normally provide. New "zeolites" have been synthesized and most of them contain many different kind of defects and at the same time a size of synthetic crystal is small. Electron Microscopy (EM) may be the best way to solve their basic structures.

Recently EM has also been extended to aplly for the study of the surface structures of "zeolites", which give information of crystal growth unit and process.

At the symposium, recent stiudies of the fine structures of "zeolites" will be presented. As a whole, the advantage of electron microscopy for the study will be discussed.