Nov. 4, 2011. London, England The General Assembly of the International Union of Pure and Applied Physics (IUPAP) approved the names of the new elements darmstadtium (Ds), element 110, as well as two other elements, roentgenium (Rg, element 111), and copernicium (Cn, element 112).
The new element was created in Darmstadt, Germany at the GSI, the Center for Heavy Ion Research, in 1996, when nine atoms were made. It took another 6 years to produce a second batch. It took fifteen years for the international committee to accept the name of the new element.
Darmstadtium contains 110 protons and has an atomic weight of 281. It was created by a linear accelerator bombarding lead ion targets with zinc ions. (The zinc atoms have to be stripped of their electrons to overcome the problem of electron cloud coulombic repulsion.) GSI's 120 meter long particle accelerator was used to smash the atoms together.
(That source was a GSI press release. A Wikipedia article on Darmstadtium claimed that nickel-62 and nickel-64 atoms were used. It's possible that different ion-smashing facilities around the world use different combinations of atoms for their studies.) Identification of the atom was done by studying the decays and identifying the daughter particles.
An international committee consisting of members of IUPAP and IUPAC concluded that the second test by Hofman, et al., was sufficient to validate GSI's claim to have created a new element. Here is the language of the final report:
The fusion–evaporation reaction using a 62Ni beam on an isotopically enriched 208Pb target produced four chains of alpha-emitting nuclides following the presumed formation of 269110 + n. The heavy residue is separated from nonfusion residues in-flight by the electromagnetic SHIP velocity filter which spatially localizes, through position-sensitive detectors, the product and its radioactive progeny. Even
in the first chain to be measured, the second and third consecutive alpha energies and delay times are
in concordance with previously studied 265Hs and 261261Sg. The redundancy of the consecutive alpha energies and delay times in the second through fourth chains measured is very reassuring. Even more so is the observation of fourth and fifth alpha particle energies and delay times in the last two chains observed that are in very good agreement with the known properties of descendants 257Rf and 253No.
JWP ASSESSMENT: Element 110 has been discovered by this collaboration.
Japan's RIKEN Discovery Research Institute confirmed the discovery of the new atom a few years later when they produced similar atoms. Six institutions are investigating darmstadtium: GSI (Darmstadt, Germany), RIKEN (Japan), Lawrence Berkeley National Labs (California, USA), Dubna (Russia), and FLNR (Russia).
Darmstadtium, which had formerly been named ununnilium (Uun), is a member of Group 10 in the periodic table, along with nickel, palladium, and platinum. Too few atoms have been made to test for bulk properties, but "like other Group 10 elements, darmstadtium is expected to have notable hardness and catalytic properties." - quoting the Wikipedia article.
To date, about 48 atoms have been manufactured. Ds has 11 isotopes whose half lives range from 11 seconds to four microseconds.
Everything2 Writeups: Articles on Chemistry, the Periodic Table, and new elements
- brutha, Darmstadtium, Dec. 2000
- avjewe, Darmstadtium, Jun. 2001
- non-buzzard, Periodic Table of the Elements, May, 2002
- rfc1394, Periodic Table of the Elements, Apr, 2001
- Wikipedia, "Darmstadtium"
- Web Elements, "Darmstadtium"
- Darmstadtium.com, "Its own web site!," wow!