|Name, symbol||ununennium, Uue|
|Alternative names||element 119, eka-francium|
|Ununennium in the periodic table|
|Standard atomic weight|| (predicted)|
|Element category||unknown, but probably an alkali metal|
|Group, period, block||group 1 (alkali metals), period 8, s-block|
|Electron configuration||[Uuo] 8s1 (predicted)
per shell: 2, 8, 18, 32, 32, 18, 8, 1 (predicted)
|Phase||unknown (could be solid or liquid)|
|Melting point||273–303 K (0–30 °C, 32–86 °F) (predicted)|
|Boiling point||903 K (630 °C, 1166 °F) (predicted)|
|Density (near r.t.)||3 g·cm−3 (predicted) (at 0 °C, 101.325 kPa)|
|Heat of fusion||2.01–2.05 kJ·mol−1 (extrapolated)|
|Oxidation states||1, 3 (predicted)|
|Ionization energies||1st: 463.1 kJ·mol−1
2nd: 1698.1 kJ·mol−1
|Atomic radius||empirical: 240 pm (predicted)|
|Covalent radius||263–281 pm (extrapolated)|
|Naming||IUPAC systematic element name|
|Most stable isotopes|
|Main article: Isotopes of ununennium|
Ununennium, also known as eka-francium or element 119, is the temporary International Union of Pure and Applied Chemistry name of a chemical element in the periodic table that has the temporary chemical symbol Uue andatomic number 119. In the periodic table of the elements, it is expected to be an s-block element, an alkali metal, and the first element in the eighth period.
Ununennium is the first element that has not yet been synthesized. To date, all attempts to synthesize this element have been unsuccessful. Its position as the seventh alkali metal suggests that it would have similar properties to the alkali metals, lithium, sodium, potassium, rubidium, caesium, and francium; however, relativistic effects may cause some of its properties to differ from those expected from a straight application of periodic trends. For example, ununennium is expected to be less reactive than caesium and francium and be closer in behavior to potassium or rubidium, and while it should show the characteristic +1 oxidation state of the alkali metals, it is also predicted to show the +3 oxidation state unknown in any other alkali metal.
No atoms were identified, leading to a limiting yield of 300 nb. Later calculations suggest that the yield of the 3n reaction (which would result in 299Uue and three neutrons as products) would be 0.5 pb.
As of May 2012, plans are under way to attempt to synthesize the isotopes 295Uue and 296Uue by bombarding a target of berkelium with titanium at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany:
The alpha-decay half-lives of 1700 nuclei with 100 ≤ Z ≤ 130 have been calculated in a quantum tunneling model with alpha-decay Q-values from different mass estimates. The alpha-decay half-lives predicted for 291–307119 are of the order of micro-seconds. The highest value of the alpha-decay half-life predicted in the quantum tunneling model with the mass estimates from a macroscopic-microscopic model is ~485 microseconds for the isotope 294119. For 302119 it is ~163 microseconds.
Being the first period 8 element, ununennium is predicted to be the next alkali metal after francium and behave much like their lighter congeners; however, it is also predicted to differ from the lighter alkali metals in some properties. Its chemistry is predicted to be closer to that of potassium or rubidium instead of caesium or francium. This is unusual as periodic trends, ignoring relativistic effects would predict ununennium to be even more reactive than caesium and francium. This lowered reactivity is due to the relativistic stabilisation of ununennium's valence electron, increasing ununennium's first ionisation energy and decreasing the metallic and ionic radii; this effect is already seen for francium. The relativistic stabilisation of the 8s orbital also increases ununennium's electron affinity far beyond that of caesium and francium; indeed, ununennium is expected to have an electron affinity higher than all the alkali metals lighter than it. Relativistic effects also cause a very large drop in the polarisability of ununennium. On the other hand, ununennium is predicted to continue the trend of melting points decreasing going down the group, being expected to have a melting point between 0 °C and 30 °C.
The stabilisation of ununennium's valence electron and thus the contraction of the 8s orbital cause its atomic radius to be lowered to 240 pm, very close to that of rubidium (247 pm), so that the chemistry of ununennium in the +1 oxidation state should be more similar to the chemistry of rubidium than to that of francium. On the other hand, the ionic radius of the Uue+ ion is predicted to be larger than that of Rb+, because the 7p orbitals are destabilised and are thus larger than the p-orbitals of the lower shells. Ununennium may also show the +3 oxidation state, which is not seen in any other alkali metal, in addition to the +1 oxidation state that is characteristic of the other alkali metals and is also the main oxidation state of all the known alkali metals: this is because of the destabilisation and expansion of the 7p3/2 spinor, causing its outermost electrons to have a lower ionisation energy than what would otherwise be expected. Indeed, many ununennium compounds are expected to have a large covalent character, due to the involvement of the 7p3/2 electrons in the bonding: this effect is also seen to a lesser extent in francium.
- Fricke, B.; Waber, J. T. (1971). "Theoretical Predictions of the Chemistry of Superheavy Elements". Actinides Reviews 1: 433–485. Retrieved 7 August 2013.
- 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.
- Bonchev, Danail; Kamenska, Verginia (1981). "Predicting the Properties of the 113–120 Transactinide Elements". J. Phys. Chem. 85: 1177–1186. doi:10.1021/j150609a021.
- Hofmann, Sigurd (2013). Overview and Perspectives of SHE Research at GSI SHIP. p. 23–32. doi:10.1007/978-3-319-00047-3.
- Lougheed, R.; Landrum, J.; Hulet, E.; Wild, J.; Dougan, R.; Dougan, A.; Gäggeler, H.; Schädel, M.; Moody, K. (1985). "Search for superheavy elements using 48Ca + 254Esg reaction". Physical Reviews C 32 (5): 1760–1763. Bibcode:1985PhRvC..32.1760L. doi:10.1103/PhysRevC.32.1760.
- Feng, Z; Jin, G; Li, J; Scheid, W (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A 816: 33. arXiv:0803.1117. Bibcode:2009NuPhA.816...33F. doi:10.1016/j.nuclphysa.2008.11.003.
- Modern alchemy: Turning a line, The Economist, May 12, 2012.
- Düllmann, Christoph E. (October 20, 2011). Superheavy Element Research: News from GSI and Mainz. Johannes Gutenberg University Mainz; GSI Helmholtzzentrum für Schwerionenforschung GmbH; Darmstadt Helmholtz Institute Mainz.
- Chowdhury, P. Roy; Samanta, C. and Basu, D. N. (2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nucl. Phys. A 789: 142–154. arXiv:nucl-th/0703086. Bibcode:2007NuPhA.789..142S. doi:10.1016/j.nuclphysa.2007.04.001.
- Chowdhury, P. Roy; Samanta, C. and Basu, D. N. (2008). "Search for long lived heaviest nuclei beyond the valley of stability". Phys. Rev. C 77 (4): 044603. arXiv:0802.3837. Bibcode:2008PhRvC..77d4603C. doi:10.1103/PhysRevC.77.044603.
- Chowdhury, P. Roy; Samanta, C. and Basu, D. N. (2008). "Nuclear half-lives for α -radioactivity of elements with 100 ≤ Z ≤ 130". At. Data & Nucl. Data Tables 94 (6): 781–806. arXiv:0802.4161. Bibcode:2008ADNDT..94..781C. doi:10.1016/j.adt.2008.01.003.
- Seaborg (c. 2006). "transuranium element (chemical element)". Encyclopædia Britannica. Retrieved 2010-03-16.
- Fricke, Burkhard (1975). "Superheavy elements: a prediction of their chemical and physical properties". Recent Impact of Physics on Inorganic Chemistry 21: 89–144. doi:10.1007/BFb0116498. Retrieved 4 October 2013.
- Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 0080379419.
- Thayer, John S. (2010). Chemistry of heavier main group elements. pp. 81, 84. doi:10.1007/9781402099755_2.
- 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.
|Extended periodic table (Large version)|