Nobelium · element 102
Named after Nobel, first claimed in Stockholm, disputed for decades, and finally credited to a Russian team
Key facts
Nobelium has one of the messiest discovery stories in the periodic table. It was claimed in Sweden, then in the United States, then in the Soviet Union, and the first two claims turned out to be wrong. The name, honouring Alfred Nobel, came from the Swedish attempt and stuck even after that work was discredited. It took until 1997 for the international bodies to settle who really found it.
The element itself is remarkable for a different reason. Alone among the actinides, nobelium prefers to lose only two electrons in solution rather than three, because its 5f shell is completely full. It is a small but telling sign that the neat pattern of the actinide series is breaking down as the elements get heavier.
Where it is found
Nobelium does not occur naturally. Its longest-lived isotope, nobelium-259, has a half-life of about 58 minutes, and most isotopes last seconds. It cannot be produced in reactors because the fermium gap stops neutron-capture chains, so it is made only in accelerators.
The classic route bombards curium targets with carbon ions. Since the 1990s, physicists have used a more efficient method: firing calcium-48 at a lead-208 target. This reaction produces nobelium-254 with an unusually high yield, enough for thousands of atoms per experiment. That is still an unimaginably small amount of matter, but it is plenty for modern single-atom detection techniques.
How it was discovered
In 1957 a team at the Nobel Institute of Physics in Stockholm reported element 102 from bombarding curium with carbon-13 and proposed the name nobelium. Berkeley and Dubna both tried to repeat the work and could not. Berkeley then announced its own discovery in 1958, based on nobelium-254 from curium and carbon-12, but later analysis showed they had misidentified the decay properties.
Between 1963 and 1966 Georgy Flerov's group at the Joint Institute for Nuclear Research in Dubna produced several isotopes of element 102 and measured their properties correctly. They proposed the name joliotium, after Frederic Joliot-Curie. A joint IUPAC and IUPAP working group reviewed all claims in 1992 and awarded discovery credit to Dubna, but in 1997 IUPAC retained nobelium as the name because it had been in use for forty years.
What we use it for
Nobelium has no applications and is used purely for research. With only atoms available, the research is exquisite. In 2016 physicists at GSI in Darmstadt performed laser spectroscopy on nobelium, making it the heaviest element to have its atomic energy levels probed directly with light. They measured the energy needed to remove its first electron and learned about the size and shape of its nucleus.
Chemically, nobelium is the strongest example of an actinide behaving like a group 2 metal. Experiments in the late 1960s showed that in solution nobelium sits happily as a +2 ion, resembling calcium or strontium, and needs a strong oxidising agent to reach +3. This confirms theoretical predictions that a filled 5f shell locks those electrons away entirely.
Reading the numbers
Nobelium's melting point of about 830 °C is an estimate from theory, and no boiling point or density is known because bulk samples do not exist. Its atomic mass of 259 is that of its longest-lived isotope. The configuration [Rn] 5f14 7s2 shows a completely filled 5f shell with two 7s electrons outside it, like ytterbium above it in the lanthanides. Losing those two 7s electrons gives a +2 ion with a stable closed shell, which explains its unusual chemistry. Its first ionisation energy, about 642 kilojoules per mole, was confirmed by the 2016 laser measurements, a rare case where an experimental value exists for such a heavy element. The strongly negative electron affinity listed in our data means a free nobelium atom will not hold an extra electron.
Safety and the environment
Nobelium exists only as a few thousand atoms at a time inside accelerator laboratories and decays within an hour. It has no environmental presence and poses no risk to anyone outside those facilities. The radiation hazards in nobelium experiments come from the accelerator beam and from the radioactive targets and decay products, all handled with standard shielding and remote procedures.
Did you know?
- Nobelium is the only actinide whose most stable form in water is the +2 ion, behaving like a very heavy calcium.
- The 1957 Swedish claim gave the element its name, even though the discovery itself was later rejected.
- In 2016 nobelium became the heaviest element to have its atomic spectrum measured with lasers, at the GSI laboratory in Germany.
- The Dubna team wanted to call element 102 joliotium; IUPAC kept nobelium for continuity.
- Nobelium-254 can be produced in relatively large numbers by fusing calcium-48 with lead-208, a reaction favoured because both nuclei are especially stable.
More in the actinides
The nearest neighbours of nobelium in the family, by atomic number.
See all 15 actinides on one page, or browse all 118 elements.
Frequently asked questions
Who discovered nobelium?
The discovery is credited to Georgy Flerov's team at Dubna in the 1960s. Earlier claims from Stockholm in 1957 and Berkeley in 1958 could not be confirmed.
Why is nobelium named after Alfred Nobel?
The Swedish team who first claimed the element in 1957 proposed the name, and it was retained even after their result was disproved because it had become so widely used.
What is nobelium used for?
Only research. It has been studied with laser spectroscopy and in solution to understand how a filled 5f shell changes the chemistry of the heaviest actinides.
How long does nobelium last?
Its longest-lived isotope, nobelium-259, has a half-life of about 58 minutes. Most isotopes decay within seconds or minutes.
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Written by Anthony. Updated September 2026. Numerical data from Periodic-Table-JSON (CC BY-SA), cross-checked against the Nobelium reference article. Spotted an error? Tell us.