UNNILENNIUM

( (Une), ) also called Element 109, an artificially produced element belonging to the transuranium group. It is predicted to have chemical properties resembling those of iridium. In 1982 West German physicists at the Institute for Heavy Ion Research (Gesellschaft fr Schwerionenforschung ) in Darmstadt synthesized an isotope of element 109 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. Unnilennium has an estimated half-life between 2 and 20 milliseconds.