Seaborgium
Seaborgium (Eka-
Tungsten) is a
chemical element in the
periodic table that has the symbol Sg and
atomic number 106. It was also known as unnilhexium (Unh), and at one time
rutherfordium was suggested. Seaborgium is a
synthetic element whose most stable
isotope 271Sg has a
half-life of 2.4
minutes. Its chemistry resembles that of tungsten.
Element 106 was discovered almost simultaneously by two different laboratories. In June
1974, an
American research team led by
Albert Ghiorso at the
Lawrence Radiation Laboratory at the
University of California, Berkeley reported creating an isotope with mass number 263 and a half-life of 1.0 s, and in September
1974, a
Soviet team led by
G. N. Flerov at the
Joint Institute for Nuclear Research at
Dubna reported producing an isotope with mass number 259 and a half-life of 0.48
s,
Because their work was independently confirmed first, the Americans suggested the name seaborgium to honor the American chemist
Glenn T. Seaborg, who is sometimes credited as a member of the American team along with Ghiorso,
J.M. Nitschke,
J.R. Alonso,
C.T. Alonso,
M. Nurmia,
E. Kenneth Hulet, and
R.W. Lougheed. The name selected by the team became controversial. An international committee decided in
1992 that the Berkeley and Dubna laboratories should share credit for the discovery.
An
element naming controversy erupted and as a result
IUPAC adopted
unnilhexium (symbol Unh) as a temporary,
systematic element name. In
1994 a committee of IUPAC recommended that element 106 be named rutherfordium and adopted a rule that no element can be named after a living person. This ruling was fiercely objected to by the
American Chemical Society. Critics pointed out that a precedent had been set in the naming of
einsteinium during
Albert Einstein's life. In
1997, as part of a compromise involving elements 104 to 108, the name seaborgium for element 106 was recognized internationally.
There are 11 known isotopes of Seaborgium, the longest-lived of which is
269Sg which decays through
alpha decay and
spontaneous fission. It has a half-life of 22 s. The shortest-lived isotope is
258Sg which also decays through alpha decay and spontaneous fission. It has a half-life of 2.9
ms.
*
Los Alamos National Laboratory - Seaborgium*
WebElements.com - Seaborgium
