The aim of this symposium is to discuss whether synchrotron orbital radiation can be available for use in the mineralogical field, on which Prof. Takeuchi gave a lecture in 1975. Informations about the materials brought out by means of X-rays are reviewed and as a result of it, the need for X-ray sources is made clear . As 'hot' X-ray sources have no room for remarkable improvements, 'cold' X-ray sources such as synchrotron orbital radiation come to be indispensable. The property of synchrotron orbital radiation and the recent research in Photon Factory are discussed.

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X-ray fluorescence trace and micro analyses using a synchrotron radiation source are of value in both research and technology. The outstanding properties of SR which serve to enhance the capability of X-ray spectrochemical analysis are the tunability of the energy spectrum, high brightness, and polarization for reduced scattered background. The state of arts and the future capability of this synchrotron radiation excited X-ray fluorescence analysis are presented. Applications of this method to earth science and materials science are also discussed.

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Synchrotron Radiation X-ray (SR) with high brightness, small divergence and continuous energy spectrum is quite prospective for X-ray experiments under pressure. High pressure studies have been performed at SSRL, CHESS, DESY and Photon Factory. Application of SR to high pressure works reveals that accuracy in determination of lattice constants becomes 10 times better than before, phase transition can be dynamically observed by time resolved measurement and measurement at temperature region higher than 1700°C can be done. Furthermore, EXAFS and XANES are measured under pressure for the first time with the aid of SR. These results are briefly introduced.

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Characteristics of minerals and inorganic substances with tunnel or porous structure are briefly reviewed. Their applications in materials science are emphasized as much as basic studies.

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Some polymorphs of manganese dioxide are characterized by tunnels of variable dimension in their structure. Tunnels having diameter of 2.8Å in α-MnO₂, such as cryptomelane and hollandite, are responsible for many interesting features. α-MnO₂ was synthesized by heating δ-MnO₂. Whereas δ-MnO₂ containing Na⁺ or K⁺ was easily converted to α-MnO₂ on heating (450°C for 4 days in air), that with Li₊ responded negatively. This is explained by the relatively small ionic radius of Li⁺ (0.60Å) which is too small to support a tunnel structure, as compared to Na⁺ (0.95 Å) and K⁺ (1.33 Å). Synthetic α-MnO₂ contains 1.7-2.3 wt% of CO₂ like it's natural counterparts e. g. todorokite from Todoroki mine with CO₂ content of 5.2 wt%. CO₂ and H₂O, adsorbed during synthesis of α-MnO₂ in air, are released at higher temperatures, which was measured by Q-mass spectrometer, α-MnO₂ kept in air for 1 month has a concommitant H₂O and CO₂ peak at 270°C, whereas δ-MnO₂ of the same condition does not have any clear peak of CO₂. α-MnO₂ kept in CO₂ atmosphere for 20 hours has CO₂ peaks at 100°C and 300°C and H₂O peak at 100°C. Release of nonpolar molecules such as O₂ and N₂ is not observed. These features of manganese dioxide phases will help to determine the structure of the mineral.

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New classes of selective heterogeneous catalysts have been prepared by the intercalation of polynuclear hydroxo complexes in smectites. Only limited number of complexes such as aluminum and zirconium hydroxo complexes are suitable for pillaring agents. New approches to extend the number of pillaring agents have been made and oxide clusters of SiO₂, Fe₂O₃, Nb₂O₅ and Ta₂O₅ were produced in the interlayer regions. Preparation of the pillared material from non-silicate layered inorganic compounds was attempted by using K₄Nb₆O₁₇·nH₂O. Nickel and aluminum hydroxo complexes were taken up into the interlayer regions, but the interlayer spacings were not as large as those of pillared clays.

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Zeolites are hydrated aluminosilicates containing alkali and alkaline-earth metal ions. Their framework structures are composed of an infinitely extending three-dimensional network of AlO₄ and SiO₄ tetrahedra, and characterized by intracrystalline void spaces such as cavities and channels surrounded with aluminosilicate network. The void spaces in zeolites are larger than those in other tectosilicates such as feldspars, and hence zeolites have more open, microporous structures. Such structural features yield various properties such as ion exchange, adsorption, molecular sieve and catalysis. In this paper, the properties of high silica zeolites, the basis on the development of acidity in zeolites, and the effects of molecular-shape selectivities in zeolite catalysts are described in connection with the compositions and structures of zeolites. In final, the catalytic conversion of methanol to hydrocarbons by use of zeolite ZSM-5 is briefly described.

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Ionic conducting substances and a diffusion mechanism are briefly reviewed. Crystalline materials are classified into three groups of one-, two- and three- dimensional conductors due to their structural characteristics. Structural studies on K_xWO₃ and on yttriastabilized zirconia, Zr(Y)O_2-x are shown as examples. Ionic conductive glasses are also discussed.

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