Hassium

Template:Elementbox header Template:Elementbox series Template:Elementbox groupperiodblock Template:Elementbox appearance Template:Elementbox atomicmass gpm Template:Elementbox econfig Template:Elementbox epershell Template:Elementbox section physicalprop Template:Elementbox phase Template:Elementbox section atomicprop Template:Elementbox crystalstruct Template:Elementbox oxistates Template:Elementbox cas number Template:Elementbox isotopes begin |- ! style="text-align:right;" | ²⁶⁹Hs | style="text-align:center;" | trace | style="text-align:right;" | 14 s | alpha | style="text-align:right;" | |- ! style="text-align:right;" | ²⁷⁰Hs | style="text-align:center;" | trace | style="text-align:right;" | 22 s | alpha | style="text-align:right;" | Template:Elementbox isotopes end Template:Elementbox footer

Hassium (Template:PronEng) is a synthetic element in the periodic table that has the symbol Hs and atomic number 108. Hassium oxidizes similar to osmium above it, to a hassium tetroxide with a lower volatility than osmium tetroxide.

History

Hassium was first synthesized in 1984 by a German research team led by Peter Armbruster and Gottfried Münzenberg at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung) in Darmstadt. The team bombarded a lead target with iron-58 nuclei to produce 3 atoms of ²⁶⁵Hs in the reaction:

$\,_{82}^{208}\mathrm {Pb} +\,_{26}^{58}\mathrm {Fe} \,\to \ \,_{108}^{265}\mathrm {Hs} +\,_{0}^{1}\mathrm {n}$

The name hassium was proposed by them, derived from the Latin name for the German state of Hessen where the institute is located.

There was an element naming controversy as to what the elements from 101 to 109 were to be called; thus IUPAC adopted unniloctium (Template:PronEng, symbol Uno) as a temporary element name for this element. In 1994 a committee of IUPAC recommended that element 108 be named hahnium (Hn). The name hassium was adopted internationally in 1997.

The GSI successfully repeated the reaction in 1994 and 75 atoms of ²⁶⁵Hs were detected along with 2 atoms of ²⁶⁴Hs from the 2n channel during the measuremnet of the excitation function. A further 20 atoms were produced in 1997. The discovery reaction was confirmed by teams at RIKEN in 2002(10 atoms) and GANIL, France in 2003 (7 atoms).

Hassium-270

Isotope 270 of Hassium, discovered by an international team of scientists led by the Technical University of Munich in December 2006, is a doubly magic isotope with an unusually long half-life of 22 seconds. The existence of such relatively stable heavy isotopes had already been theoretically predicted, with some theories suggesting Hassium-270 may form part of an island of stability.

External links

• WebElements.com - Hassium
• Apsidium - Hs