Einsteinium

化学的特性man-made radioisotope; identified by Ghiorso and colleagues at Berkeley in December 1952, as part of debris from first large thermonuclear explosion; chemical properties similar to those of holmium; ionic radius of Es+++ is 0.0925 nm; has lowest enthalpy of vaporization of any of the divalent elements; cub, a=0.575 nm; discovered in 1952; t1/2 of 253Es is 20.5 days, t1/2 of 254Es is 276 days, t1/2 of 255Es is 40 days [HAW93] [KIR78]

来歴The name of Es derives from “Albert Einstein”, the Geituan born physicist who proposed the theory of relativity. A collaboration of American scientists G. R. Choppin, S. G. Thompson, A. Ghiorso, and B. G. Harvey, from the Argonne National Laboratory near Chicago, Illinois, the Los Alamos Scientific Laboratory in Los Alamos, New Mexico and at the University of California lab in Berkeley, CA, first found 252Es in the radioactive debris from the first large thermonuclear bomb explosion, nicknamed “Mike,” which took place at Enewetak atoll, Marshall Islands in the Pacific on November 1, 1952. The longest halflife associated with this unstable element is 472 day 252Es.