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Yoshio Takéuchi (1924-2009)

[Yoshio Takeuchi]

Yoshio Takéuchi, Emeritus Professor of the U. of Tokyo, passed away at the age of 85 on July 5, 2009 in Tokyo, Japan. He was born in Tokyo on Jan. 20, 1924 and educated at the U. of Tokyo. During his PhD course he studied crystal structures of mineral polymorphs with T. Ito and R. Sadanaga, where his idea on the symmetry elements gliding of unit-cell twinned space groups contributed to the publication of X-ray Study on Polymorphism (T. Ito, Maruzen, 1950). In 1952 he went to M. J. Buerger's laboratory at MIT to determine the crystal structure of terramycin hydrochloride by using vector sets in Patterson space (Proc. Natl Acad. Sci. 46, 1366, 1960). Leaving for home in 1956, he was consecutively lecturer, associate professor and professor of the  Mineralogical Institute at the U. of Tokyo. After his retirement in 1984, he moved to Nihon University to teach students mineralogy and crystallography until 1998.

He was a member of the IUCr Commission on Crystallographic Computing in 1960s, a co-editor of Zeitschrift für Kristallographie and a member and secretary of the Japanese National Committee for Crystallography until the 1980s. He served on various international bodies such as the Joint Committee on Powder Diffraction Standards (JCPDS) and the International Centre for Diffraction Data (ICDD). He was active in Japan, serving as a president of the Crystallographic Society of Japan as well as the Mineralogical Society of Japan. He contributed to organizing the IUCr72 Kyoto Congress and the establishment of the Photon Factory synchrotron facility and large-scale computing centers among universities.

He published numerous research papers, in which his main and deep interest was made up into a book of Tropochemical Cell-Twinning (A Structure-Building Mechanism in Crystalline Solids), published in 1997 by Terra Scientific Publishing Co., Tokyo. The free pdf files are available on the website In 1978 he introduced the concept of tropochemical cell-twinning (TCT) as a crystallographic mechanism of building complex structures. The TCT mechanism with crystallographic slips can characterize the crystal structure and crystal chemistry of the homologous series and non-stoichiometric compounds.

He was always a kind, enthusiastic and open-minded gentleman with a gift for finding younger research scientists. He was interested in serendipity and recently engaged in the editing and Japanese translation of the fairy tale of The Three Princes of Serendip. His many friends mourn his passing.

Satoshi Sasaki