What is Nobelium?

Alfred Nobel, a Swedish chemist who lived from 1833 to 1896, is known for discovering dynamite and for using his fortune to institute the prestigious group of awards known as the Nobel Prizes. It is less well-known that the synthetic element with atomic number 102, nobelium, was named after him. Nobelium was discovered in 1957, the next to the last of the transuranic actinoids to be discovered.

The discovery of nobelium has an interesting history. Its discovery was announced in 1957 by physicists at the Nobel Institute in Sweden. The discovery was made as a result of bombarding curium with carbon nuclei, and confirmed at several other laboratories, with the name nobelium proposed. But then the findings were withdrawn. In 1958, a team at the University of California at Berkeley, tried again, this time using carbon ions, and though unable to confirm the earlier reports, they were able to, eventually, produce an isotope of 102.

The team of Albert Ghiorso, Glenn T. Seaborg, Torbjørn Sikkeland, and John R. Walton — given the choice of name — suggested that the original designation of nobelium and No stand, and so it was. But more recent investigation in 1992 has shown that while the Berkeley team may have detected element 102, the first definitive detection dates from Dubna in 1966, and the International Union of Pure and Applied Chemistry (IUPAC) recognizes the scientists from Dubna as the discoverers.

The Dubna scientists proposed the name Joliotium with the symbol Jo in recognition of Frédéric Joliot-Curie, but this name was not used. For a short time, the name flerovium with the atomic symbol Fl was used at the IUPAC’s suggestion to refer to the element. But this has been superseded by the IUPAC’s recognition that the name nobelium, having been used for 30 years, was spread throughout the literature and should be kept, both for that reason and to honor Alfred Nobel.

Nobelium has been synthesized from the decay of elements that are heavier, including Hassium, Lawrencium, Rutherfordium, and Seaborgium. However, insufficient amounts of nobelium exist to either create a radiation hazard — which it would do in sufficient quantities — or to describe such aspects of it as its appearance.

Seventeen isotopes have been described, with the most stable — Nobelium-259 — having a half-life of 58 minutes. It is expected that other isotopes may have longer half-lives. The controversies surrounding its original discovery have extended to the discovery of its isotopes. The 2003 claim from scientists at the Flerov Laboratory of Nuclear Reactions (FLNR) to have found the lightest isotope so far known was retracted, when the intimations of Nobelium-249 were found to have been caused by Nobelium-250.