Darmstadtium

Darmstadtium is a synthetic, highly radioactive chemical element with the symbol Ds and atomic number 110. Its most stable known isotope, darmstadtium-281, has a half-life of about 14 seconds. The element was first created in November 1994 at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, after which it is named. The discovery team, led by Peter Armbruster, Gottfried Münzenberg, and Sigurd Hofmann, produced a single atom of darmstadtium-269 by bombarding a lead-208 target with nickel-62 nuclei. Two more atoms were detected later that month, though a fourth reported atom was later retracted due to fabricated data. The team also synthesized nine atoms of a heavier isotope using nickel-64. Earlier attempts at the Joint Institute for Nuclear Research in Dubna and the Lawrence Berkeley National Laboratory had been inconclusive. In the periodic table, darmstadtium is a d-block transactinide element in period 7 and group 10, but no chemical experiments have yet confirmed it behaves as the heavier homologue to platinum. It is calculated to have properties similar to its lighter group 10 homologues: nickel, palladium, and platinum. The element has no stable or naturally occurring isotopes; eleven radioactive isotopes with atomic masses from 267 to 281 have been reported, though darmstadtium-267 remains unconfirmed. Most decay primarily through alpha decay, with some undergoing spontaneous fission. Heavier isotopes tend to be more stable, and theoretical models predict that the undiscovered isotope darmstadtium-294, with a magic number of 184 neutrons, could have an alpha decay half-life on the order of centuries. The name darmstadtium was officially recommended by IUPAC in August 2003, replacing the systematic placeholder name ununnilium and earlier proposals such as hahnium and becquerelium.