Isotopes of ununoctium

From Wikipedia, the free encyclopedia
Jump to: navigation, search

Ununoctium (Uuo) is a synthetic element created in particle colliders, and thus a standard atomic mass cannot be given. Like all synthetic elements, it has no stable isotopes. The first (and so far only) isotope to be synthesized was 294Uuo in 2006; it has a half-life of 890 microseconds.


Z(p) N(n)  
isotopic mass (u)
half-life decay mode(s) daughter
294Uuo 118 176 294.21392(71)# 890 µs α 290Lv


  • Values marked # are not purely derived from experimental data, but at least partly from systematic trends.
  • Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values from Ame2003 denote one standard deviation. Values from IUPAC are expanded uncertainties.


Theoretical calculations done on the synthetic pathways for, and the half-life of, other isotopes have shown that some could be slightly more stable than the synthesized isotope 294Uuo, most likely 293Uuo, 295Uuo, 296Uuo, 297Uuo, 298Uuo, 300Uuo and 302Uuo.[1][2][3] Of these, 297Uuo, might provide the best chances for obtaining longer-lived nuclei,[1][3] and thus might become the focus of future work with this element. Some isotopes with many more neutrons, such as some located around 313Uuo, could also provide longer-lived nuclei.[4]

Target-projectile combinations leading to Z=118 compound nuclei[edit]

The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with Z=118.

Target Projectile CN Attempt result
160Gd 136Xe 296Uuo* Reaction yet to be attempted
208Pb 86Kr 294Uuo* Failure to date
232Th 64Ni 296Uuo* Reaction yet to be attempted
238U 58Fe 296Uuo* Reaction yet to be attempted
244Pu 54Cr 298Uuo* Reaction yet to be attempted
248Cm 50Ti 298Uuo* Reaction yet to be attempted
250Cm 50Ti 300Uuo* Reaction yet to be attempted
249Cf 48Ca 297Uuo* Successful reaction
252Cf 48Ca 300Uuo* Reaction yet to be attempted
257Fm 40Ar 297Uuo* Reaction yet to be attempted

Theoretical calculations on evaporation cross sections[edit]

The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.

DNS = Di-nuclear system ; σ = cross section

Target Projectile CN Channel (product) σ max Model Ref
208Pb 86Kr 294Uuo 1n (293Uuo) 0.1 pb DNS [5]
208Pb 85Kr 293Uuo 1n (292Uuo) 0.18 pb DNS [5]
252Cf 48Ca 300Uuo 3n (297Uuo) 1.2 pb DNS [6]
251Cf 48Ca 299Uuo 3n (296Uuo) 1.2 pb DNS [6]
249Cf 48Ca 297Uuo 3n (294Uuo) 0.3 pb DNS [6]


  1. ^ a b P. Roy Chowdhury; C. Samanta; D. N. Basu (January 26, 2006). "α decay half-lives of new superheavy elements". Physical Review C. 73: 014612. arXiv:nucl-th/0507054free to read. Bibcode:2006PhRvC..73a4612C. doi:10.1103/PhysRevC.73.014612. Retrieved 2008-01-18. 
  2. ^ C. Samanta; P. Roy Chowdhury; D. N. Basu (April 6, 2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nuclear Physics A. 789 (1–4): 142–154. arXiv:nucl-th/0703086free to read. Bibcode:2007NuPhA.789..142S. doi:10.1016/j.nuclphysa.2007.04.001. Retrieved 2008-01-18. 
  3. ^ a b G. Royer; K. Zbiri; C. Bonilla (2004). "Entrance channels and alpha decay half-lives of the heaviest elements". Nuclear Physics A. 730 (3–4): 355–376. arXiv:nucl-th/0410048free to read. Bibcode:2004NuPhA.730..355R. doi:10.1016/j.nuclphysa.2003.11.010. Retrieved 2008-01-18. 
  4. ^ S. B. Duarte; O. A. P. Tavares; M. Gonçalves; O. Rodríguez; F. Guzmán; T. N. Barbosa; F. García; A. Dimarco (2004). "Half-life predictions for decay modes of superheavy nuclei". Journal of Physics G: Nuclear and Particle Physics. 30 (10): 1487–1494. Bibcode:2004JPhG...30.1487D. doi:10.1088/0954-3899/30/10/014. Retrieved 2008-01-18. 
  5. ^ a b Feng, Zhao-Qing; Jin, Gen-Ming; Li, Jun-Qing; Scheid, Werner (2007). "Formation of superheavy nuclei in cold fusion reactions". Physical Review C. 76 (4): 044606. arXiv:0707.2588free to read. Bibcode:2007PhRvC..76d4606F. doi:10.1103/PhysRevC.76.044606. 
  6. ^ a b c Feng, Z; Jin, G; Li, J; Scheid, W (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A. 816 (1–4): 33–51. arXiv:0803.1117free to read. Bibcode:2009NuPhA.816...33F. doi:10.1016/j.nuclphysa.2008.11.003. 
Isotopes of ununseptium Isotopes of ununoctium Isotopes of ununennium
Table of nuclides