einsteinium(redirected from Element 99)
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n. Symbol Es
A synthetic transuranic element first produced by neutron irradiation of uranium in a thermonuclear explosion and now usually produced in the laboratory by irradiating plutonium and other elements. The isotopes with the longest half-lives are Es-252 (472 days) and Es-254 (276 days). Atomic number 99; melting point 860°C (estimated); valence 2, 3. See Periodic Table.
[After Albert Einstein.]
(Elements & Compounds) a metallic transuranic element artificially produced from plutonium. Symbol: Es; atomic no: 99; half-life of most stable isotope, 252Es: 276 days
[C20: New Latin, named after Albert Einstein]
ein•stein•i•um(aɪnˈstaɪ ni əm)
a transuranic element. Symbol: Es; at. no.: 99.
Symbol Es A synthetic, radioactive metallic element of the actinide series that is usually produced by bombarding plutonium or another element with neutrons. The most stable isotope of einsteinium has a half-life of 1.3 years. Atomic number 99. See Periodic Table.
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|Noun||1.||einsteinium - a radioactive transuranic element produced by bombarding plutonium with neutrons|