Definition of berkelium in US English:



  • The chemical element of atomic number 97, a radioactive metal of the actinide series. Berkelium does not occur naturally and was first made by bombarding americium with helium ions.

    • ‘Berkelium does not occur naturally in the biosphere and so normally never presents a risk.’
    • ‘Following up on berkelium, dubnium and californium, researchers at the University of Berkely in California, stumbled upon am element with atomic number 117 about a year ago.’
    • ‘All known isotopes of berkelium are radioactive, with the longest-lived being berkelium - 247, with a half life of 1,380 years.’
    • ‘The New Yorker wondered why they had not gone for broke, naming these two universitium and offium so as to reserve berkelium and californium for the next two elements.’
    • ‘For example, researchers at the Berkeley laboratory first discovered elements 97 and 98 and then suggested naming them berkelium and californium in honor of Berkeley, California, where the research was done.’


1949: from Berkeley (where it was first made) + -ium.