Darmstadtium (pronounced
/dɑrmˈʃtætiəm/&_160;(
listen))
darm-SHTAT-ee-əm, formerly known as
ununnilium, is a
chemical element with the symbol
Ds and
atomic number 110. It is placed as the heaviest member of group 10 but a sufficiently stable isotope is not known which would allow chemical experiments to confirm its place. This
synthetic element is one of the so-called
super-heavy atoms and was first synthesized in 1994. The longest-lived and heaviest isotope known is
281Ds with a
half-life of ~10 s although a possible isomer,
281bDs has an unconfirmed
half-life of about 4 minutes.
Darmstadtium was first created on November 9, 1994 at the Gesellschaft für Schwerionenforschung (GSI) in Arheilgen, a northern suburb of Darmstadt, Germany by Peter Armbruster and Gottfried Münzenberg, under the direction of professor Sigurd Hofmann. Four atoms of it were detected by a nuclear fusion reaction caused by bombarding a lead-208 target with nickel-62 ions [1]
In the same series of experiments, the same team also carried out the reaction using heavier nickel-64 ions. During two runs, 9 atoms of 271Ds were convincingly detected by correlation with known daughter decay properties [2]
The IUPAC/IUPAP Joint Working Party (JWP) recognised the GSI team as discoverers in their 2001 report.[3]
