Abstract
Compared with common inorganic materials, the smectite group of clay minerals have many unusual physical and chemical properties. Precise characterization on the minerals has, however, been hindered by the luck of large single crystals, and our current understanding and use of these materials are limited in the form of polycrystalline aggregates of under-micronmeter size particles. Because X-ray and electron diffraction methods, the common tool for structure analysis, enhance the periodic nature of subject, the local and random structure is difficult to see particularly. Some characteristics emphasized in a small particles are described for the cases of multiple-twin-domain particle of gold and the clean (111) surface of silicon single crystal. Similar futures may be present in smectite of the same order of size. A single crystal of smectite may, therefore, be a key for finer understanding and use. The current state of the studies focusing on synthesis of high-crystalline smectine is also described.
