How would you synthesize Ununennium


Properties (if known)
Name, symbol, atomic numberUnunennium, Uue, 119
Element categoryUnknown
Group, period, block1, 8, p
CAS number54143-88-3
Atomic massestimated 295 u
Electron configuration[Og] 8s1 (?)
Electrons per energy level2, 8, 18, 32, 32, 18, 8, 1
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions. Values ​​that are particularly questionable are marked with (?)

Ununennium is a currently hypothetical chemical element with atomic number 119, it is also called Eka-Francium designated.

In the periodic table it is between the 118Oganesson (first synthesized in 2006) and the 120Unbinilium. The element does not occur in nature, it could only be produced by nuclear reaction in the future.

In the extended periodic table (it is outside the "normal" periodic table) it belongs to the alkali metals and the transactinoids. The name is the temporary systematic IUPAC name and stands for the three digits (Un-un-enn-ium) of the ordinal number. Furthermore, the 8th period, which has not yet been explored, begins with him. In the periodic table of the elements, it is expected to be an s-block element, an alkali metal, and the first element of the eighth period.

Synthetic routes

Ununennium is the element with the smallest atomic number that has not yet been synthesized. Several attempts were made by American, German, and Russian teams to synthesize this element. They have all been unsuccessful. Experiments suggest that the synthesis of Ununennium (and following elements) is likely to be much more difficult than that of the previous elements. Perhaps it is already the penultimate element that can be synthesized with current technology. Further trials by Japanese and Russian teams are planned for 2019-2020.[outdated] Its position as the seventh alkali metal suggests that it could have properties similar to the lighter elements of main group 1. However, relativistic effects can lead to some properties differing from the expected trends. For example, it is expected that Ununennium is less reactive than cesium and francium and behaves more like potassium or rubidium and could also have a +3 oxidation number in addition to the characteristic +1 oxidation number of the alkali metals.

Failed synthesis attempts

As early as 1985 an attempt was unsuccessful at the linear accelerator superHILAC in Berkeley to generate Ununennium by bombarding Einsteinium-254 with calcium-48-ions.[1]

\ ({\ displaystyle \, _ {\ 99} ^ {254} \ mathrm {Es} + \, _ {20} ^ {48} \ mathrm {Ca} \ to \, _ {119} ^ {302} \ mathrm {Uue} ^ {*} \ qquad \ to \ qquad {\ text {no atoms}}} \)

This reaction is unlikely to be successful because it is very difficult to make a sufficient amount of the Einsteinium target.

Target-projectile combinations for cores with Z = 119

The following table shows all the combinations for targets and projectiles that could be used to generate nuclei with a charge number of 119, the half-life of which does not stand in the way (T.1/2 > 0.2 a):

Target projectile product
core HWZ (a) core HWZ (a) corecorecomment
208Pbstable 87Rb48 billion 295Uue292Uuetoo neutron poor °)
232Th14 billion 65Custable 297Uue294Uue
238U4.5 billion 59Costable 297Uue294Uue
238U4.5 billion 60Co5,3 298Uue295Uue
237Np2.1 million 58Festable 295Uue292Uuetoo neutron poor °)
237Np2.1 million 60Fe2.6 million 297Uue294Uue
244Pooh80 million 55Mnstable 299Uue296Uue
243At the7370 54Crstable 297Uue294Uue
248Cm340000 51Vstable 299Uue296Uue
250Cm9000 51Vstable 301Uue298Uue
247Bk1380 50Tistable 297Uue294Uue
248Bk9 50Tistable 298Uue295Uue
249Bk0,88 50Tistable 299Uue296Uue
249Cf351 45Scstable 294Uue291Uuetoo neutron poor °)
250Cf13 45Scstable 295Uue292Uuetoo neutron poor °)
251Cf900 45Scstable 296Uue293Uuetoo neutron poor °)
252Cf2,6 45Scstable 297Uue294Uue
252It1,3 48Approx~ stable 300Uue297Uue
254It0,75 48Approx~ stable 302Uue299Uue

°) If one follows the trend of the last isotopes produced by 115Moscovium and 117Tenness, these nuclei contain far too few neutrons to have longer half-lives.

Prediction of the decay characteristics

The alpha decay half-lives of 1700 isotopes with a charge number between 100 and 130 were predicted on the basis of model calculations.[2][3][4] The half-lives found for 291–307Uue amount to a few microseconds. The isotope should have the longest half-life of nearly half a millisecond 294Uue have.

Individual evidence

  1. ↑ R. W. Lougheed, J. H. Landrum, E. K. Hulet, J. F. Wild, R. J. Dougan, A. D. Dougan, H. Gäggeler, M. Skull, K. J. Moody, K. E. Gregorich, G. T. Seaborg: Search for superheavy elements using the 48Ca + 254ItG reaction. In: Physical Review C.. Volume 32, No. 5, 1985, pp. 1760-1763, doi: 10.1103 / PhysRevC.32.1760
  2. ↑ C. Samanta, P. R Chowdhury, D. N. Basu: Predictions of alpha decay half lives of heavy and superheavy elements. In: Nuclear Physics, Section A.. Volume 789, No. 1-4, 2007, pp. 142-154, doi: 10.1016 / j.nuclphysa.2007.04.001, arxiv: nucl-th / 0703086v2
  3. ↑ P. Roy Chowdhury, C. Samanta, D. N. Basu: Search for long lived heaviest nuclei beyond the valley of stability. In: Physical Review C (Nuclear Physics). Volume 77, No. 4, 2008, pp. 044603-10, doi: 10.1103 / PhysRevC.77.044603, arxiv: 0802.3837v1
  4. ↑ P. R Chowdhury, C. Samanta, D. N. Basu: Nuclear half-lives for α-radioactivity of elements with 100 ≤ Z ≤ 130. In: Atomic Data and Nuclear Data Tables. Volume 94, No. 6, 2008, pp. 781-806, doi: 10.1016 / j.adt.2008.01.003, arxiv: 0802.4161v2

Web links

Categories:Period 8 element | Transactinoid | Chemical element

Status of information: 04/29/2021 3:07:28 AM CEST

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