106SgSeaborgium[269]

A real sample of the element Seaborgium — Synthetic element — no real sample has ever been photographed

Seaborgium (Sg)

“The first element in history named after a living scientist — Glenn Seaborg saw his own name enter the periodic table in 1997.”

View group 6 →View period 7 →See in trends →

Atomic number106

Atomic mass[269]

Group6

Period7

BlockD-block

PhaseSolid

Electron structure

How its electrons are arranged

[Rn] 5f¹⁴ 6d⁴ 7s²

Shell 1

2e⁻

Shell 2

8e⁻

Shell 3

18e⁻

Shell 4

32e⁻

Shell 5

32e⁻

Shell 6

12e⁻

Shell 7

2e⁻

Computed from the aufbau principle, with known real-world exceptions applied automatically.

🎯 Exam focus

Questions to practise

Try each question yourself first — then open it to read the full model answer.

1Which reaction — oxygen-18 striking californium-249 — created seaborgium at Berkeley in 1974, and why was Dubna’s rival claim set aside?

Model answerIn 1974 a Berkeley team including Albert Ghiorso and Glenn Seaborg bombarded a californium-249 target with oxygen-18 ions and identified Sg-263 — atoms that lasted less than a second. Dubna had reported a rival claim, but it could not be confirmed by other experiments, so the discovery credit went to Berkeley.

2What did the 2014 synthesis of seaborgium hexacarbonyl Sg(CO)₆ prove about organometallic chemistry at the superheavy limit?

Model answerThe 2014 experiment fused seaborgium atoms with carbon monoxide to make $\mathrm{Sg(CO)_{6}}$ , the first organometallic compound of any superheavy element. It proved that carbon–metal bonds survive even in atoms where relativistic effects distort the electron cloud: seaborgium formed a volatile hexacarbonyl just like tungsten’s $\mathrm{W(CO)_{6}}$ , carrying organometallic chemistry to the very edge of the table.

3Quiz programmes love asking which element was first named for a living person — explain why the answer is seaborgium.

Model answerSeaborgium was the first element in history named after a living person. Glenn Seaborg — Nobel laureate and co-discoverer of ten elements including plutonium — was alive when IUPAC approved the name in 1997, and photographs of him pointing to “his” element became classroom favourites; he said the honour meant even more to him than his 1951 Nobel Prize.

4How does seaborgium’s minute-scale longest half-life shape the way chemists design their experiments with it?

Model answerAtoms must be caught before they die. With minute-scale isotopes like Sg-269, every step is automatic: single atoms emerge from an accelerator, are swept off within seconds by flowing gas, and race through gas-phase or aqueous chemistry while still alive — and because each run yields one atom, the sequence repeats thousands of times to build usable statistics.

5Which Group 6 metals does seaborgium sit beneath, and what does its d-block position predict about its oxide and chloride chemistry?

Model answerSeaborgium sits beneath chromium, molybdenum and tungsten in Group 6, Period 7, d-block. That position predicts hexavalent, tungsten-like chemistry — and experiments confirm it: seaborgium forms the volatile oxychloride $\mathrm{SgO_{2}Cl_{2}}$ just as tungsten forms $\mathrm{WO_{2}Cl_{2}}$ , and it behaves like tungsten in solution.

6Why was naming element 106 after Glenn Seaborg controversial in the 1990s, and how did IUPAC resolve the matter in 1997?

Model answerBecause tradition said elements honour only the dead, and Seaborg was very much alive — the living Nobel laureate who co-discovered ten elements. Traditionalists objected, and IUPAC delayed approval for years before its 1997 ruling finally confirmed seaborgium, ending the Transfermium Wars and letting Seaborg see his own name in the table.

Quick answers

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Electron configurationThe full arrangement, step by step ValencyHow many bonds it forms Atomic massThe standard weight, explained Metal or nonmetalWhich family it belongs to Everyday usesWhere you meet it daily

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The notes

About the element

Characteristics

A synthetic Group 6 transition metal — the superheavy twin of molybdenum and tungsten — produced a few atoms at a time.
Its longest-lived isotopes, such as Sg-269, persist for minutes at best; the original 1974 atoms survived under a second.
Its chemistry has genuinely been studied: gas-phase work found volatile $\mathrm{SgO_{2}Cl_{2}}$ like tungsten’s $\mathrm{WO_{2}Cl_{2}}$ , and solution experiments confirmed tungsten-like behaviour.
Relativity matters here: slowed 7s electrons pull inward, so seaborgium’s bonding drifts subtly away from tungsten’s.

Appearance

Seaborgium exists only as isolated radioactive atoms that fade away within minutes. Theory says it should be a dense, silvery Group 6 metal of the tungsten family, with relativistic effects nudging its properties away from a simple “heavier tungsten” picture.

Real world

Where you meet it

✦ Uses

Testing Group 6 chemistry at the relativistic limit — comparing seaborgium with molybdenum and tungsten, atom by atom.
Seaborgium hexacarbonyl, $\mathrm{Sg(CO)_{6}}$ , made in 2014, carried organometallic chemistry to the edge of the periodic table for the first time.
Its isotopes’ decay chains feed nuclear-mass mapping in the region approaching the predicted island of stability.

◍ Everyday examples

Photographs of an elderly Glenn Seaborg pointing to “his” element on the periodic table are favourites in chemistry classrooms worldwide.
The 1951 Nobel Prize in Chemistry for the transuranium elements links this element’s namesake to every Nobel-season news feature.
Science olympiad and quiz competitions often ask which element was the first named after a living scientist — the answer sits in Period 7, Group 6.

Story

History & name

In 1974 a Berkeley team including Albert Ghiorso and Glenn Seaborg bombarded californium-249 with oxygen-18 ions and identified Sg-263, whose atoms lasted less than a second. A rival Soviet claim from Dubna could not be confirmed, and credit went to Berkeley. The name seaborgium — honouring the living Nobel laureate who co-discovered ten elements — annoyed traditionalists so much that IUPAC delayed approval until 1997. Seaborg remarked that having an element named after him meant even more to him than his 1951 Nobel Prize.

Name originHonours Glenn T. Seaborg, Nobel laureate and co-discoverer of ten elements including plutonium.

Neighbours

Nearby elements

The elements that sit right beside this one on the table — often the closest chemical cousins.

104RfRutherfordium[267]105DbDubnium[268]107BhBohrium[270]108HsHassium[269]