106SgSeaborgium[269]
Transition metal

Seaborgium (Sg)

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

Atomic number106
Atomic mass[269]
Group6
Period7
BlockD-block
PhaseSolid
Electron structure

How its electrons are arranged

Sg
[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.

Study

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 SgO₂Cl₂ like tungsten’s WO₂Cl₂, 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, 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.