hassium

hassium [has′ē əm]

n.

〚ModL, after the L name for HESSE², where new elements were created in a nuclear physics laboratory + -IUM〛

a radioactive chemical element with a very short half-life: a transactinide produced by bombarding lead with high-energy nuclear particles: symbol, Hs: at. no., 108: see the periodic table of elements in the Reference Supplement

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has·si·um (häʹsē-əm) n. Symbol Hs

An artificially produced radioactive element with atomic number 108 whose most long-lived isotopes have mass numbers of 264 and 265 with half-lives of 0.08 milliseconds and 2 milliseconds, respectively. Also called unniloctium. See table at element.

  [From Medieval Latin Hassia, Hesse (German state containing Darmstadt, where the element was first synthesized).]

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▪ chemical element

 an artificially produced element belonging to the transuranium group, atomic number 108. It was synthesized and identified in 1984 by West German researchers at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung [GSI]) in Darmstadt. On the basis of its position in the periodic table of the elements, it is expected to have chemical properties similar to those of osmium.

      The GSI research team, led by Peter Armbruster, produced an isotope of hassium in a fusion reaction by irradiating lead-208 with ions of iron-58. The isotope, which has a mass number of 265, is exceedingly unstable and has a half-life of only 2 milliseconds. Experiments conducted by A.G. Demin and other researchers at the Joint Institute for Nuclear Research in Dubna, Russia, U.S.S.R., suggested the existence of two more isotopes of hassium with mass numbers of 263 and 264.

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