Sg Seaborgium
Proposed Name
Atomic Number: 106
Atomic Symbol: Sg
Atomic Weight: 263
Electron
Configuration: [Rn]7s²5f¹⁴6d⁴
History
In June 1974, members of the Joint Institute for Nuclear Research in Dubna,
U.S.S.R., reported their
discovery of Element 106, which they reported to have synthesized. Glenn
Seaborg was part of this
group, and the element was named in his honor. Seaborgium is often still
referred to as Element 106
because the international committee in charge of names changed the rules. They
decided retroactively it
couldn't be named after a living person.
In September 1974, workers of the Lawrence Berkeley and Livermore Laboratories
also claimed creation
Element 106 "without any scientific doubt." The LBL and LLL Group used the
Super HILAC to
accelerate 18O ions onto a 249Cf target.
Element 106 was created by the reaction 249Cf(18O, 4N)263X, which decayed by
alpha emission to
rutherfordium, and then by alpha emission to nobelium, which in turn further
decayed by alpha between
daughter and granddaughter. The element so identified had alpha energies of
9.06 and 9.25 MeV with a
half-life of 0.9 +/- 0.2 s.
At Dubna, 280-MeV ions of 54Cr from the 310-cm cyclotron were used to strike
targets of 206Pb,
207Pb, and 208Pb, in separate runs. Foils exposed to a rotating target disc
were used to detect
spontaneous fission activities. The foils were etched and examined
microscopically to detect the number
of fission tracks and the half-life of the fission activity.
Other experiments were made to aid in confirmation of the discovery. Neither
the Dubna team nor the
Berkeley-Livermore Group has proposed a name as of yet for element 106
(unnilhexium).