Nobelium
Element 102 · Actinide
Nobelium is a synthetic actinide with a famously contested discovery: teams in Stockholm, Berkeley, and Dubna all claimed it in the late 1950s and 1960s, with credit now generally given to the Dubna group. Like its lanthanide counterpart ytterbium, nobelium favors the +2 oxidation state because of its filled 5f shell. Only tracer amounts have ever been produced, so most properties are predicted with limited experimental data. Nobelium is entirely radioactive; its isotopes decay within minutes to hours.
Key facts
| Atomic number | 102 |
|---|---|
| Atomic weight | [259] |
| Category | Actinide |
| Group / Period | — / 7 |
| Block | f |
| Electron configuration | [Rn] 5f14 7s2 |
| Common oxidation states | +2, +3 |
| State at STP | Solid |
| Electronegativity | 1.3 |
| Melting point | 827 °C (estimated) |
Occurrence
Nobelium is entirely synthetic, made by bombarding curium targets with carbon ions in accelerators. It decays within minutes to hours.
Applications
Tracer chemistry of late actinides
Studies of the +2 oxidation state stability
No commercial applications
Common compounds
- Nobelium(II) chloride (NoCl2, tracer scale)
- Nobelium(III) oxide (No2O3, predicted)
Nobelium is named after Alfred Nobel, founder of the Nobel Prizes; its discovery was claimed by three different labs before being settled.
Data source: IUPAC standard atomic weights 2021