Seaborgium (Sg)

Seaborgium (symbol Sg) is the chemical element with atomic number 106: a transition metal, radioactive, made artificially, with an atomic mass of 269 u. Discovered in 1974 (Albert Ghiorso et al. (Berkeley)).

Seaborgium honors Glenn Seaborg, co-discoverer of ten elements including plutonium, and the chemist who reorganized the periodic table by setting apart the actinide row. It was named during his lifetime, a controversial first. Only a few atoms have ever been made at a time; the rare experiments show it behaves like tungsten. Its most stable known isotope, seaborgium-269, has a half-life of a few minutes.

Key facts

Atomic number: 106
Symbol: Sg
French name: Seaborgium
Atomic mass: 269 u
Molar mass: [269] g/mol
Family: Transition metals
Position: period 7, group 6, d-block
State at 0 °C: Unknown
First ionization energy: 757 kJ/mol
Electron configuration: [Rn] 5f¹⁴ 6d⁴ 7s²
Radioactive: yes
Discovery: 1974, Albert Ghiorso et al. (Berkeley)

Origin of the name

In honor of the chemist Glenn T. Seaborg.

What does seaborgium look like?

Never observed in visible amounts; predicted to be a very dense metal, perhaps silvery.

Where is seaborgium found?

Absent from nature.

How is seaborgium produced?

In 1974, the Berkeley and Livermore team produced it by bombarding a californium-249 target with a beam of oxygen-18 ions in an accelerator. Its longest-lived isotopes now show up in the decay chains of heavier elements such as flerovium and livermorium.

Top producers

United States (Berkeley, Livermore)
Russia (Dubna)
Germany (GSI)
Japan (RIKEN)

What is seaborgium used for?

Basic research only
Checking whether superheavy elements still follow the trends of the periodic table

In everyday life

None — it exists only for moments in the lab

Role in living things

No biological role.

Hazards of seaborgium

Radioactive, but produced atom by atom: no practical danger.

Cosmic origin

Human-made: Does not exist (or barely) in nature: synthesized in a reactor or accelerator.

History of seaborgium

In 1974, Albert Ghiorso, Kenneth Hulet and their colleagues from Berkeley and Livermore identified element 106, while Dubna simultaneously claimed a disputed discovery. The American results were confirmed in 1993. IUPAC hesitated to accept the name of a living person, then approved “seaborgium” in 1997.

Did you know?

Seaborg liked to point out that mail could reach him at “Seaborgium, Lawrencium, Berkelium, Californium, Americium” — in other words, the Lawrence lab in Berkeley, California, in America.
In 2014, an international team at RIKEN (Japan) made the first carbonyl compound of a superheavy element, seaborgium hexacarbonyl, with a handful of atoms.
Seaborg died in 1999, two years after “his” element was officially recognized.

Isotopes of seaborgium

No stable isotopes; seaborgium isotopes live a few minutes at most.

seaborgium-263: radioactive, half-life 900 ms. The element's first synthesized isotope, in 1974.
seaborgium-269: radioactive, half-life 14 min. The longest-lived known, a decay product of flerovium.

Related elements

Same family (transition metals): Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), Yttrium (Y), Zirconium (Zr), Niobium (Nb), Molybdenum (Mo), Technetium (Tc), Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Silver (Ag), Cadmium (Cd), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt), Gold (Au), Mercury (Hg), Rutherfordium (Rf), Dubnium (Db), Bohrium (Bh), Hassium (Hs).

Same column (group 6): Chromium (Cr), Molybdenum (Mo), Tungsten (W).