Roentgenium
Unununium redirects here. For operating system, please see Unununium. Roentgenium (former temporary name:
unununium or
eka-gold) is a
chemical element in the
periodic table that has the symbol
Rg (former temporary symbol:
Uuu) 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 probably would appear as a heavy, solid, shiny metal. Due to the
inert pair effect, it should be colored like
gold.
It was
first created 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. Some research has referred to it as "
eka-
gold".
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
s. 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.
The elements in
Group 11 used to informally be called the
coinage metals, due to their historical use in coins. It is unlikely that roentgenium can be used to make coins since all of its isotopes are radioactive with very short half-lifes.
*
Darmstadtium (Ds) —
Ununbium (Uub)
*
WebElements.com - Roentgenium*
IUPAC: Proposal of name roentgenium for element 111*
IUPAC: Element 111 is named roentgenium*
Apsidium - Roentgenium Element 111
