Roentgenium

Roentgenium (IPA: /ˌr(ə/o)ʊntˈgɛniəm/, formerly Unununium) is a chemical element in the periodic table that has the symbol Rg and atomic number 111, making it one of the super-heavy atoms. It is a synthetic element whose longest-lived isotope has a mass of 280 and a half-life of 3.6 seconds. Due to its presence in Group 11, it is a transition metal and so would probably appear as a heavy, solid, shiny metal.^{[citation needed]} Due to the inert pair effect, it should be colored like gold.^{[citation needed]}

1 History
2 Isotopes
3 See also
4 External links

[edit] History

It was discovered by Peter Armbruster, Gottfried Münzenber, and their team working at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany on December 8, 1994. Only three atoms of it were observed (all ²⁷²Rg), by the fusion of bismuth-209 and nickel-64 in a linear accelerator. (Nickel was bombarded onto the bismuth target.)

The name roentgenium was accepted as a permanent name on November 1, 2004 in honor of Wilhelm Röntgen; before this date, the element was known under the temporary IUPAC systematic element name unununium (IPA: /ˌuːˌnuːˈnuːniəm/, symbol Uuu). Some research has referred to it as eka-gold.

The official baptism took place at GSI, on Friday November 17, 2006, in presence of Annette Schavan, the Federal German Minister of Research.

[edit] Isotopes

Three isotopes of roentgenium are known. The longest-lived of these is ²⁸⁰Rg, which decays through alpha decay and has a half-life of 3.6 second. The shortest-lived isotope is ²⁷²Rg, which decays through alpha decay and has a half life of 1.5 ms. The other known isotope, ²⁷⁹Rg, decays through alpha decay and has a half-life of 170 ms.