|Name, Symbol, Number||hassium, Hs, 108|
|Chemical series||transition metals|
|Group, Period, Block||8, 7, d|
|Appearance||unknown, probably silvery|
white or metallic gray
|Standard atomic weight||(278) g·mol−1|
|Electron configuration||perhaps [Rn] 5f14 6d6 7s2|
(guess based on osmium)
|Electrons per shell||2, 8, 18, 32, 32, 14, 2|
|Phase||presumably a solid|
|Oxidation states||8, 7, 6, 5, 4, 3, 2, 1, −1|
|CAS registry number||54037-57-9|
Hassium (pronounced /ˈhæsiəm/) 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.
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 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 (pronounced /ˌjuːn
ɪlˈɒktiəm/, symbol Uno) as a temporary element name for this element. In 1994 a committee of IUPAC recommended that element 108 be named hahnium. The name hassium was adopted internationally in 1997.
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.
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