Seaborgium · element 106
The first element officially named after a living person, a chemist who helped find ten of them
Key facts
Glenn Seaborg co-discovered ten elements, including plutonium, redrew the bottom of the periodic table by proposing the actinide series, and shared a Nobel Prize in 1951. In 1994 his colleagues wanted to put his name on element 106 while he was still alive to enjoy it. That request set off a three-year argument, because no element had ever been named after a living person before.
Seaborgium sits below tungsten in group 6. It is a metal on paper, but no one has ever seen a piece of it. The atoms made so far have lived for a few minutes at most, and yet chemists have managed to make compounds with them and watch how they behave.
Where it is found
Seaborgium is entirely artificial. It has never been found in rocks, seawater, meteorites or stars, and there is no reason to expect it anywhere in nature, because every known isotope decays far too quickly to survive. The total number of atoms ever produced is probably in the low thousands at most, made over half a century of experiments.
The original Berkeley experiment fired oxygen-18 nuclei at a target of californium-249, producing seaborgium-263. For chemistry experiments, researchers prefer to bombard curium-248 with neon-22, which yields seaborgium-265 and 266. These live for seconds to tens of seconds, just long enough to be swept out of the target chamber in a stream of gas and reacted with something.
How it was discovered
In 1974 two laboratories claimed element 106 within months of each other. Yuri Oganessian's team at Dubna fired chromium-54 at lead-207 and reported spontaneous fission events. Albert Ghiorso's team at Berkeley, working with Seaborg's group, detected seaborgium-263 through its alpha decays to known daughter nuclei, a much stronger form of proof. After years of review, IUPAC credited the Berkeley group in 1993.
The Berkeley team proposed seaborgium in 1994. IUPAC objected the same year, arguing that elements should not be named after living people, and suggested rutherfordium for 106 instead. American chemists pushed back hard, pointing out that einsteinium and fermium had been named while their honourees were alive, even if the names were only made public after their deaths. In 1997 IUPAC relented. Seaborg lived to see it, dying in 1999.
What we use it for
Seaborgium has no uses. There is never enough of it, and it never lasts long enough. Its value is entirely scientific, and in particular it has been a proving ground for superheavy chemistry.
In 1997 an international team working at GSI in Darmstadt let freshly made seaborgium atoms react with oxygen and chlorine. The product behaved like the volatile oxychlorides that molybdenum and tungsten form, confirming that seaborgium really is a group 6 metal. Solution experiments showed it acting like tungsten rather than like uranium, proving that the actinide series had truly ended. In 2014 a team at RIKEN in Japan went further and made seaborgium hexacarbonyl, the first compound of a superheavy element containing a metal-carbon bond.
Reading the numbers
The figures here are predictions or reflect the longest-lived isotope. The atomic mass of 269 is simply the mass number of the most stable known isotope, whose half-life is a few minutes. The predicted density of about 35 grams per cubic centimetre is nearly twice that of tungsten, a result of both heavier nuclei and the way relativity shrinks the inner electron shells. No melting or boiling point has been measured.
The predicted configuration [Rn] 5f14 6d4 7s2 gives six outer electrons, matching chromium, molybdenum and tungsten and pointing to a +6 oxidation state. Here the experiments have not delivered any big surprises. Seaborgium looks like a heavier, better-behaved tungsten. That is itself an interesting result, because for some of its neighbours, such as dubnium, the pattern is less tidy.
Safety and the environment
Every isotope of seaborgium is radioactive, with half-lives measured in milliseconds to minutes. This sounds alarming, but it means the element cannot accumulate anywhere. An atom made this morning is long gone by lunchtime. The few atoms produced are created inside heavily shielded accelerator facilities and are detected precisely because they decay. There is no seaborgium in the environment, no stockpile, and no plausible way for anyone outside a nuclear physics laboratory to be exposed.
Did you know?
- Glenn Seaborg liked to point out that a letter could reach him using only element names: seaborgium, lawrencium (for his laboratory), berkelium, californium, americium.
- In 2014 researchers made seaborgium hexacarbonyl, a molecule with one seaborgium atom surrounded by six carbon monoxide groups, using only a few dozen atoms.
- IUPAC's 1994 proposal would have called element 106 rutherfordium and element 104 dubnium. Both suggestions were overturned in 1997.
- Seaborg helped discover plutonium in 1940 and later led the chemistry that separated it for the Manhattan Project.
- Seaborgium-263, the isotope from the 1974 discovery, has a half-life of around a second. The longest-lived isotopes known today last a few minutes.
More in the superheavy elements
The nearest neighbours of seaborgium in the family, by atomic number.
See all 15 superheavy elements on one page, or browse all 118 elements. Also listed under the transition metals.
Frequently asked questions
Who is seaborgium named after?
Glenn T. Seaborg, the American chemist who co-discovered plutonium and nine other elements and won the Nobel Prize in Chemistry in 1951. He was alive when the name was approved in 1997, making seaborgium the first element officially named after a living person.
Why was the name seaborgium controversial?
IUPAC had a rule of not naming elements after living people and initially rejected the proposal in 1994. After strong protests from the American Chemical Society and others, it reversed the decision in 1997.
What is the half-life of seaborgium?
It depends on the isotope. The shortest-lived last only milliseconds, while the most stable known isotopes, around seaborgium-269 and 271, survive for a few minutes before decaying.
Does seaborgium have any uses?
No. It exists only a few atoms at a time and decays within minutes. Its only role is in research, where it helps chemists check whether the periodic table's group 6 pattern holds for very heavy atoms.
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Written by Anthony. Updated September 2026. Numerical data from Periodic-Table-JSON (CC BY-SA), cross-checked against the Seaborgium reference article. Spotted an error? Tell us.