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meitnerium [mīt nir′ē əm]n.a radioactive chemical element with a very short half-life: a transactinide produced by bombarding bismuth with high-energy nuclear particles: symbol, Mt; at. no., 109: see the periodic table of elements in the Reference Supplement
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meit·ner·i·um (mīt-nûrʹē-əm) n. Symbol MtAn artificially produced radioactive element with atomic number 109 whose most long-lived isotopes have mass numbers of 266 and 268 with half-lives of 3.4 milliseconds and 70 milliseconds, respectively. Also called unnilennium. See table at element.[After Meitner, Lise.]* * *
an artificially produced element belonging to the transuranium group, atomic number 109. It is predicted to have chemical properties resembling those of iridium.In 1982 West German physicists at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung [GSI]) in Darmstadt synthesized an isotope of meitnerium with a mass number of 266. Using a high-energy linear accelerator, the GSI investigators, under the direction of Peter Armbruster, bombarded bismuth-209 targets with beams of iron-58 ions for roughly 10 days. The resultant fusion reaction between the bismuth and iron atoms yielded only a single nucleus of the new element; however, the sensitivity of the detection technique employed left little doubt as to the validity of the identification. Meitnerium has an estimated half-life between 2 and 20 milliseconds.* * *
Universalium. 2010.
