Periodic  Table of the Elements
Proposed Name
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Atomic Number:106
Atomic Symbol:Sg
Atomic Weight:271
Electron Configuration:[Rn]7s25f146d4
Total Isotopes20
Total Isomers4
Radioactive Isotopes16
Stable Isotopes0

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Man Made ElementIn 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.

Glenn SeaborgIn 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).

Sources: Los Alamos National Laboratory; CRC Handbook of Chemistry and Physics; American Chemical Society
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