|hassium (hä'sē-əm) Pronunciation Key
A synthetic, radioactive element that is produced by bombarding lead with iron ions. Its most long-lived isotopes have mass numbers of 264 and 265 with half-lives of 0.08 millisecond and 2 milliseconds, respectively. Atomic number 108. See Periodic Table.
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 fur 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.
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