|Unbiquadium in the periodic table|
|Name, symbol, number||unbiquadium, Ubq, 124|
|Group, period, block||n/a, 8, g|
|Standard atomic weight||unknown|
|Electron configuration||[Uuo] 6f3 8s2 8p1
2, 8, 18, 32, 32, 21, 8, 3
|Oxidation states||6 (predicted)|
|Naming||IUPAC systematic element name|
In 2008, a team at GANIL, France, published results indicating that nuclei of unbiquadium had been produced at very high excitation energy, which underwent fission with measurable lifetimes. This result suggests a strong stabilizing effect at Z=124 and points to the next proton shell at Z>120, not at Z=114 as previously thought.
Synthesis of unbiquadium nuclei
Scientists at GANIL attempted to measure the direct and delayed fission of compound nuclei of elements with Z=114, 120, and 124 in order to probe shell effects in this region and to pinpoint the next spherical proton shell. This is because having complete nuclear shells (or, equivalently, having a magic number of protons or neutrons) would confer more stability on the nuclei of such superheavy elements, thus moving closer to the island of stability. In 2006, with full results published in 2008, the team provided results from a reaction involving the bombardment of a natural germanium target with uranium ions:
The team reported that they had been able to identify compound nuclei fissioning with half-lives > 10−18 s. A compound nucleus is a loose combination of nucleons that have not arranged themselves into nuclear shells yet. It has no internal structure and is held together for its brief existence only by the forces generated during the collision between the target and projectile nuclei. It is estimated that it requires around 10−14 s for the nucleons to arrange themselves into nuclear shells, at which point the compound nucleus becomes an nuclide, and this number is used by IUPAC as the minimum half-life a claimed isotope must have to potentially be recognised as being discovered. Thus, the GANIL experiments do not count as a discovery of element 124. Although a half-life of just over 10−18 seconds is very short, the ability to measure such decays indicated a strong shell effect at Z=124. A similar phenomenon was found for Z=120 but not for flerovium (Z=114).
The name unbiquadium is an IUPAC systematic element name, the temporary name and symbol assigned to newly synthesized and not-yet-synthesized chemical elements. A transuranic element receives a permanent name and symbol only after its synthesis has been confirmed. Transuranic elements beyond californium are always artificially produced, and usually end up being named for a scientist or the location of a laboratory that does work in atomic physics.
- Haire, Richard G. (2006). "Transactinides and the future elements". In Morss; Edelstein, Norman M.; Fuger, Jean. The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN 1-4020-3555-1.
- Pyykkö, Pekka (2011). "A suggested periodic table up to Z≤ 172, based on Dirac–Fock calculations on atoms and ions". Physical Chemistry Chemical Physics 13 (1): 161–8. Bibcode:2011PCCP...13..161P. doi:10.1039/c0cp01575j. PMID 20967377.
- Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. p. 590. ISBN 978-0-19-960563-7.
- Morjean, M.; Charvet, J.L.; Chbihi, A.; Chevallier, M.; Cohen, C.; Dauvergne, D.; Dayras, R.; Drouart, A.; Frankland, J.D.; Jacquet, D.; Kirsch,, R.; Laget, M.; Lautesse, P.; L'Hoir, A.; Marchix, A.; Nalpas, L.; Parlog, M.; Ray, C.; Schmitt, C.; Stodel, C.; Tassan-Got, L.; Volant, C. (February 5, 2007). Direct experimental evidence for very long fission times of super-heavy elements. Retrieved January 27, 2013.
|Extended periodic table (Large version)|