The production and confirmation of elements 110 and higher required the development ofnew equipment. In 1994 Peter Armbruster’s team used the Heavy Ion Research Laboratory’slinear accelerator (SHIP) located in Darmstadt, Germany, to create a few atoms of element110 that had an atomic mass of 267. The researchers bombarded a thin sheet of lead withhigh-energy ions of nickel. They “fired” over one billion (1×1018) nickel ions at the leadtarget for seven days, resulting in the fusion of just one or two atoms of ununnilium 110.Uun’s isotope, now known as darmstadtium-269, has a half-life of about 0.00017 seconds asit spontaneously decays into hassium-277 and four alpha particles in the process. Both thesingle atoms produced and their short half-lives have made it difficult to identify the elementUun and impossible to perform any chemistry or confirm the predicted chemical and physicalproperties and characteristics of element 110.
同位体
There are a total of nine isotopes of Uun (Ds), ranging from Uun-267 to Uun-281, with half-lives ranging from 0.17 milliseconds to 1.1 minute.
名前の由来
Named for the German city of Darmstadt.
来歴
(Darmstadt, city in Germany), Ds. In 1987
Oganessian et al., at Dubna, claimed discovery of Darmstadtium.
Their experiments indicated the spontaneous fissioning nuclide
272110 with a half-life of 10 ms. More recently a group led by
Armbruster at G.S.I. in Darmstadt, Germany, reported evidence
of 269110, which was produced by bombarding lead for many days
with more than 1018 nickel atoms. A detector searched each collision
for Element 110’s distinct decay sequence. On November 9,
1994, evidence of 110 was detected. In 2003 IUPAC approved the
name darmstadtium, symbol Ds, for Element 110. Seven isotopes
of Element 110 are now recognized.
使用
None are known except as an interest in nuclear laboratories.
定義
A radioactive metallic element that does not occur naturally on the Earth. It is made either by bombarding a lead target with nickel nuclei or by bombarding a plutonium target with sulfur nuclei. There are several isotopes; the most stable is 281Ds, with a half-life of about 1.6 minutes. The chemical properties of darmstadtium should be similar to those of platinum. The element is named for Darmstadt, the place in Germany where it was discovered.
危険性
None, beyond minor risks from radiation because only a few atoms of darmstadtium areproduced at a time, and all of its isotopes exist for only a small fraction of second.
