Structure
Not a diagram of dots on rings — a Monte-Carlo sample of the actual probability density |ψ|² for each occupied subshell. Drag to rotate. Blue and violet mark opposite signs of the wavefunction, which is what makes bonding possible.
Measured values
Every bar shows where seaborgium sits among all 118 elements for that property.
Sources: IUPAC 2021 standard atomic weights · CRC Handbook of Chemistry and Physics · NIST. Values marked ~ are predicted rather than measured.
Size, to scale
Radius 247 pm — that is 0.247 nm, so about 2024 million of them side by side would span a millimetre.
Thermal range
Neither transition has been measured for seaborgium — too few atoms have ever existed at once.
The story
Named for Glenn Seaborg while he was still alive — a first for the periodic table.
Seaborgium was discovered in June 1974 by Albert Ghiorso, J. M. Nitschke, José R. Alonso, Carol T. Alonso, M. Nurmia, G. T. Seaborg, and others at the Lawrence Berkeley National Laboratory. This discovery continued the American leadership in superheavy element synthesis during the Cold War era.
The team used Berkeley's Super Heavy Ion Linear Accelerator (SuperHILAC) to bombard californium-249 targets with oxygen-18 ions, producing seaborgium-263 with a half-life of 0.9 seconds. This represented a major breakthrough in superheavy element synthesis techniques.
The element was named "seaborgium" after Glenn T. Seaborg (1912-1999), Nobel Prize-winning chemist who discovered ten transuranium elements and revolutionized nuclear chemistry. Remarkably, Seaborg was still alive when the element was named, making it the first element named after a living person.
Soviet scientists at Dubna contested the discovery priority, leading to another Cold War naming dispute. IUPAC initially rejected "seaborgium" in 1994 but reversed this decision in 1997, officially recognizing the name and Berkeley's discovery priority.
The 2025 discovery of seaborgium-257 by international collaboration using the TASCA separator at GSI represents the latest advancement in seaborgium research, demonstrating continued progress in superheavy element physics with 22 observed decay events providing detailed nuclear data.
Applications
Seaborgium serves as the crucial test case for understanding Group 6 chemical behavior in superheavy elements, helping scientists determine how chromium, molybdenum, and tungsten chemical properties extend into the superheavy region under extreme relativistic conditions.
Scientists use seaborgium to investigate nuclear shell effects and stability patterns in superheavy nuclei. The recent 2025 discovery of seaborgium-257 provides new insights into fission properties and shell effects that influence superheavy element behavior.
Seaborgium enables groundbreaking studies of relativistic effects in chemical bonding where electron orbital shapes and energies are dramatically altered by extreme nuclear charge. These studies validate theoretical predictions about superheavy element chemistry.
Research teams employ seaborgium to study complex decay chains including alpha decay sequences, spontaneous fission, and K-isomeric states. Recent discoveries of K-isomeric states in seaborgium-259 open new avenues for exploring nuclear structure phenomena.
Seaborgium research drives innovation in ultra-sensitive analytical techniques including gas-filled separators like TASCA, advanced particle detection arrays, and sophisticated data analysis methods for identifying individual superheavy atoms.
Seaborgium applications are exclusively limited to world-leading nuclear physics facilities including GSI Helmholtz Centre in Germany, RIKEN in Japan, Berkeley Lab in the USA, and JINR in Russia. These facilities use seaborgium for cutting-edge superheavy element research.
Research teams utilize seaborgium in advanced nuclear spectroscopy including alpha-decay energy measurements, gamma-ray detection, and nuclear lifetime studies. The 2025 discovery of seaborgium-257 demonstrates the precision achievable in modern superheavy element research.
Scientists perform significant individual atom chemical studies with seaborgium, investigating oxidation states and chemical bonding using gas-phase chromatography and extraction techniques at the absolute limits of analytical chemistry capabilities.
Seaborgium research necessitates development of state-of-the-art detection systems including the TASCA separator, position-sensitive detectors, and advanced timing systems that represent a high point of nuclear physics instrumentation technology.
Where it comes from
0 mg/kg of Earth's crust · more abundant than 0% of elements
Seaborgium exists only through artificial synthesis in particle accelerators and has never been detected naturally on Earth or in stellar phenomena. This superheavy element represents matter that exists nowhere else in the universe except through human technological intervention.
Scientists create seaborgium by bombarding californium-249 targets with oxygen-18 ions, or by bombarding lead-206/208 targets with chromium-52 ions in linear accelerators. The recent seaborgium-257 discovery used chromium-52 bombardment of lead-206 targets.
The most stable seaborgium isotope, 271Sg, has a half-life of only 2.4 minutes, while the newly discovered 257Sg survives just 12.6 milliseconds. These extremely short lifetimes demonstrate the challenge of studying superheavy element properties.
Seaborgium production occurs at the level of individual atoms per experiment, with the 2025 seaborgium-257 discovery observing just 22 decay events. Worldwide annual production totals perhaps hundreds to low thousands of atoms across all research facilities.
Unlike elements formed through stellar nucleosynthesis or cosmic ray interactions, seaborgium cannot exist naturally due to its extremely short half-life and highly specific nuclear reaction requirements. It represents a high point of artificial element creation technology.
Handling
Seaborgium is radioactive. It has no stable isotope — every nucleus decays. Handling requires appropriate shielding and licensing.
MAXIMUM DANGER: Seaborgium is an intensely radioactive superheavy element that undergoes alpha decay and spontaneous fission, emitting dangerous high-energy particles, neutrons, and gamma radiation. Even individual atoms pose theoretical health risks requiring high containment protocols.
Seaborgium isotopes emit high-energy alpha particles and undergo spontaneous fission with the newly discovered seaborgium-257 showing both alpha decay and spontaneous fission pathways. This creates multiple simultaneous radiation hazards including fission fragments and neutron emissions.
Research requires maximum containment systems including heavily shielded hot cells, robotic handling equipment, neutron detection and shielding, and continuous multi-parameter radiation monitoring. Emergency decontamination and specialized medical facilities must be immediately available.
All materials contacting seaborgium become extremely hazardous nuclear waste requiring specialized long-term storage and environmental monitoring. Contamination creates persistent radiation hazards lasting multiple decades, necessitating the strictest nuclear safety protocols.
Quick answers
Seaborgium (symbol Sg) is element 106 on the periodic table, a transition metal in period 7, group 6. Named for Glenn Seaborg while he was still alive — a first for the periodic table. At room temperature it is a solid, and it is radioactive.
[Rn] 5f¹⁴ 6d⁴ 7s², giving 7 occupied shells holding 2, 8, 18, 32, 32, 12, 2 electrons respectively.Seaborgium has no stable isotope, so it has no standard atomic weight. The figure quoted, 271, is the mass number of its longest-lived known isotope.
Seaborgium has a density of 35 g/cm³. Water is 1.0 g/cm³, so a block of seaborgium is about 35× heavier.
Seaborgium was discovered in 1974 by Lawrence Berkeley National Laboratory. It is named after glenn T. Seaborg.
Seaborgium does not occur naturally on Earth in any meaningful quantity — it is made in a reactor or an accelerator.
Yes. Seaborgium has no stable isotope — every one of its nuclei decays. It does not occur in usable quantities in nature and must be synthesised.