It is shown that zeolites are one of the potential candidates for dielectric container to make low- dimensional materials, and that the characterization of the defects in zeolites, which affect the physical and chemical properties seriously, is an important subject in zeolite science.
The high capability of high resolution electron microscopy for tackling these problems is confirmed by showing two examples, i, e., direct observations of Se atoms incorporated in the channels of mordenite, and sodalite and offretite intergrowths in erionite.