FAJANS, KASIMIR

FAJANS, KASIMIR (1887–1975), U.S. physical chemist who did pioneering work on radioactivity and isotopes. Fajans was born in Warsaw, and after studying in Leipzig, Heidelberg, and Zurich, worked with Rutherford in Manchester. After a period on the staff of the Technische Hochschule at Karlsruhe, Fajans went to the University of Munich, where in 1923 he became full professor of physical chemistry. In 1932 he secured support from the Rockefeller Foundation for the establishment of an institute of physical chemistry in Munich, of which he became director, but in 1935 he was forced by the Nazis to leave the institute. He emigrated to the U.S. and in 1936 became professor of chemistry at the University of Michigan at Ann Arbor. Fajans, with Goehring, discovered the element 91 (uranium X2 or brevium), the more stable isotope of which (called protoactinium) was discovered independently a little later by Hahn and Meitner and also by Soddy and Cranston. Of Fajans' contributions to scientific journals, many are concerned with brevium, other work on radioactive transformations, and the chemistry of the radioactive elements. But he was also active in numerous other fields of physical chemistry. For some time he was coeditor of Zeitschrift für Kristallographie and associate editor of the Journal of Physical and Colloid Chemistry. He wrote Radioaktivität und die neueste Entwicklung der Lehre von den chemischen Elementen (19202), Physikalisch-chemisches Praktikum (1929, with J. Wuest), Radioelements and Isotopes; Chemical Forces and Optical Properties of Substances (1931), and Quanticule Theory of Chemical Bonding (1960). -BIBLIOGRAPHY: Lange, in: Zeitschrift fuer Elektrochemie, 61 (1957), 773–4. (Samuel Aaron Miller)