Darmstadtium

Editor's note. In May 2003 ununnilium was renamed darmstadtium.

Latin for 1-1-0.

Also the name for the chemical element 110.

Abbreviation: Ds (formerly Uun)
Atomic Mass: 269
Half-life: 0.27 ms
Protons/Electrons: 110
Number of Neutrons: 159
Classification: Transition Metal
It is an synthetic, metallic element first created 1994 from ⁶²Ni and ²⁰⁸Pb at the GSI in Darmstadt, Germany.

Darmstadtium
Atomic Symbol Ds
Atomic Number 110
Atomic Weight 271. Six different isotopes have been synthesized.
presumably a solid at 298 K
Color unknown, but probably metallic and silvery white or grey in appearance

Darmstadtium is a synthetic element that is not present in the environment. Isolation of an observable quantity of darmstadtium has never been achieved, and thus darmstadtium has no known uses. The reactivity of darmstadtium is unknown, but is assumed to be similar to platinum and palladium.

Darmstadtium's most stable isotope, darmstadtium-281, has a half-life of about 1.1 minutes. It decays into hassium-277 through alpha decay (according to http://education.jlab.org/itselemental/ele110.html).

Darmstadtium was first synthesized on November 9, 1994 at the Gesellschaft für Schwerionenforschung a.k.a the Institute for Heavy Ion Research a.k.a. GSI in Darmstadt, Germany. After ten days of bombardiing Bismuth(209) with Iron(58) they produced one single atom unambiguously identified as meitnerium, via
Lead(208) + Nickel(62) = Darmstadtium(269) + 1 neutron
Lead(208) + Nickel(64) = Darmstadtium(271) + 1 neutron

It can also be produced in the breakdown of Uub via
Ununbium(281) = Darmstadtium(277) + Helium(4)

Before May 5, 2003, no name had yet been recommended for element 110, which was therefore called ununnilium, from the Latin roots un for one and nil for zero, under a convention for neutral temporary names proposed by the International Union of Pure and Applied Chemistry (IUPAC) in 1980. The new name is based on Darmstadt, Germany, the city in which it was first created.

                 platinum
                     ^
meitnerium <-- darmstadtium --> roentgenium

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

1. brutha, Darmstadtium, Dec. 2000
2. avjewe, Darmstadtium, Jun. 2001
3. non-buzzard, Periodic Table of the Elements, May, 2002
4. rfc1394, Periodic Table of the Elements, Apr, 2001

Internet References

1. Wikipedia, "Darmstadtium"
2. Web Elements, "Darmstadtium"
3. Darmstadtium.com, "Its own web site!," wow!