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einsteinium (Es)




A synthetic, radioactive, metallic element of the actinide series. The isotope 253Es was first identified in 1952 by G. R. Choppin and co-workers at the University of California at Berkeley; this was after it was found as a decay product of 238U produced by the first large hydrogen bomb explosion. Eleven isotopes are known, the most stable of which is 254Es (half-life 276 days). Only a few milligrams of einsteinium are made each year, from plutonium in nuclear reactors. Atomic number 99.


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   • INORGANIC CHEMISTRY