Studies on clays and clay minerals with special reference to the chemical affinity

Abstract

In considering the historical information about the development of the studies on clays and clay minerals, it is known that there are several large trends of studies which started in olden times and have kept on developing till the present, and will promise to make further advance in future, having interesting fundamentals, high potentialities, and wide application. Attention may first be drawn to the development of the field of the studies on the chemical affinity of clay minerals. This article attempts to account the outline of the studies in this field. The contents, however, are slightly different from the traditional review the object is, rather, to see what light may be thrown on typical phenomena in this field by a general and inclusive concept.(1) In the first place, the writer gave a brief account of the special quality of the studies on “acid clay” performed by K. Kobayashi (the late Emeritus Professor of Waseda University) and his collaborators. The studies are regarded to be the foremost works in this field.(2) The role of the chemical affinity of clay minerals has been demonstrated in various chemical reactions between clay minerals and inorganic or organic materials. In the second place, therefore, the nature of clay-organic complexes or clay-organic derivatives was briefly explained with special reference to their structural implications.(3) The chemical and structural behaviours resulted from the chemical affinity of clay minerals have been studied in several aspects in terms of surface-chemical and topochemical reactions, epitaxy, and catalysis. In the third place, the writer gave a brief account of the studies on epitaxy observed among various kinds of materials, and stressed its significant in clay mineralogy.(4) In the fourth place, the writer stressed that it is significant and interesting to study the typical phenomena resulted from the chemical affinity of clay minerals from a point of view standing on the general and inclusive concept, that is, the template theory (“Matrizenprincips”) set fourth by H. Seifert.(5) In learning the current studies concerning the role of clays and clay minerals in the aspects such as the generation of petroleum, the origin of life, and the environmental science, particular attention was paid on the facts and concepts that clay mineral have acted as templates.