Ununoctium (Uuo) was only very recently synthesized; all data are theoretical. It has no stable isotopes. A standard atomic mass cannot be given.
Table
nuclide
symbol |
Z(p) |
N(n) |
isotopic mass (u)
|
half-life |
nuclear
spin |
representative
isotopic
composition
(mole fraction) |
range of natural
variation
(mole fraction) |
| excitation energy |
| 293Uuo |
118 |
175 |
293.21467(129)# |
|
|
|
|
| 294Uuo |
118 |
176 |
|
|
|
|
|
Notes
* 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
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][2] Of these, 297Uuo, might provide the best chances for obtaining longer-lived nuclei,[1][2] and thus might become the focus of future work with this element. Some isotopes with much more neutrons, such as some located around 313Uuo, could also provide longer-lived nuclei.[3]
Target-projectile combinations leading to Z=118 compound nuclei
The below table contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=118.
| Target |
Projectile |
CN |
Attempt result |
| 208Pb |
86Kr |
294118 |
Failure to date |
| 232Th |
64Ni |
296118 |
Reaction yet to be attempted |
| 238U |
58Fe |
296118 |
Reaction yet to be attempted |
| 244Pu |
54Cr |
298118 |
Reaction yet to be attempted |
| 248Cm |
50Ti |
298118 |
Reaction yet to be attempted |
| 249Cf |
48Ca |
297118 |
Successful reaction |
Theoretical calculations on evaporation cross sections
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 |
294118 |
1n (293118) |
0.1 pb |
DNS |
[4] |
| 208Pb |
85Kr |
293118 |
1n (292118) |
0.18 pb |
DNS |
[4] |
| 252Cf |
48Ca |
300118 |
3n (297118) |
1.2 pb |
DNS |
[5] |
| 251Cf |
48Ca |
299118 |
3n (296118) |
1.2 pb |
DNS |
[5] |
| 249Cf |
48Ca |
297118 |
3n (294118) |
0.3 pb |
DNS |
[5] |
References
* Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
1. ^ a b P. Roy Chowdhury, C. Samanta, and D. N. Basu (January 26, 2006). "α decay half-lives of new superheavy elements". Phys. Rev. C 73: 014612. Retrieved 2008-01-18.
2. ^ a b c C. Samanta, P. Roy Chowdhury and D. N. Basu (April 6, 2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nuclear Physics A 789: 142–154. Retrieved 2008-01-18.
3. ^ S B Duarte, O A P Tavares, M Gonçalves, O Rodríguez, F Guzmán, T N Barbosa, F García and A Dimarco (2004). "Half-life predictions for decay modes of superheavy nuclei". J. Phys. G: Nucl. Part. Phys. 30: 1487–1494. doi:10.1088/0954-3899/30/10/014. http://www.iop.org/EJ/abstract/0954-3899/30/10/014/. Retrieved 2008-01-18.
4. ^ a b Feng, Zhao-Qing (2007). "Formation of superheavy nuclei in cold fusion reactions". Physical Review C 76: 044606. doi:10.1103/PhysRevC.76.044606.
5. ^ a b c Feng, Z (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A 816: 33. doi:10.1016/j.nuclphysa.2008.11.003.
Isotopes of ununseptium Isotopes of ununoctium Isotopes of ununennium
