Ununennium

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properties
Properties (if known)
Name , symbol , atomic number Ununennium, Uue, 119
Element category Unknown
Group , period , block 1 , 8 , p
CAS number 54143-88-3
Atomic
Atomic mass estimated 295 u
Electron configuration [ Og ] 8 s 1 (?)
Electrons per energy level 2, 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 known as Eka - Francium .

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

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. 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, in addition to the characteristic +1 oxidation number of alkali metals, could also have a +3 oxidation number.

Failed synthesis attempts

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

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 cores with a charge number of 119 whose half-life does not stand in the way (T 1/2 > 0.2 a):

Target projectile product
core HWZ (a) core HWZ (a) core core comment
208 Pb stable 87 Rb 48 billion 295 uue 292 uue too neutron poor °)
232 Th 14 billion 65 Cu stable 297 Uue 294 uue
238 U 4.5 billion 59 Co stable 297 Uue 294 uue
238 U 4.5 billion 60 Co 5.3 298 uue 295 uue
237 Np 2.1 million 58 feet stable 295 uue 292 uue too neutron poor °)
237 Np 2.1 million 60 feet 2.6 million 297 Uue 294 uue
244 Pu 80 million 55 mn stable 299 uue 296 uue
243 On 7370 54 Cr stable 297 Uue 294 uue
248 cm 340000 51 V stable 299 uue 296 uue
250 cm 9000 51 V stable 301 Uue 298 uue
247 Bk 1380 50 Ti stable 297 Uue 294 uue
248 Bk 9 50 Ti stable 298 uue 295 uue
249 Bk 0.88 50 Ti stable 299 uue 296 uue
249 Cf 351 45 Sc stable 294 uue 291 uue too neutron poor °)
250 cf 13 45 Sc stable 295 uue 292 uue too neutron poor °)
251 Cf 900 45 Sc stable 296 uue 293 uue too neutron poor °)
252 Cf 2.6 45 Sc stable 297 Uue 294 uue
252 it 1.3 48 approx ~ stable 300 uue 297 Uue
254 it 0.75 48 approx ~ stable 302 Uue 299 uue

°) If one follows the trend of the last generated isotopes of 115 Moscovium and 117 Tenness, 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. The half-lives found for 291–307 Uue amount to a few microseconds. The isotope 294 Uue should have the longest half-life of almost half a millisecond .

Individual evidence

  1. ↑ RW Lougheed, JH Landrum, EK Hulet, JF Wild, RJ Dougan, AD Dougan, H. Gäggeler, M. Skull, KJ Moody, KE Gregorich, GT Seaborg: Search for superheavy elements using the 48 Ca + 254 Es g reaction . In: Physical Review C . tape 32 , no. 5 , 1985, pp. 1760-1763 , doi : 10.1103 / PhysRevC.32.1760 .
  2. ↑ C. Samanta, P. R Chowdhury, DN Basu: Predictions of alpha decay half lives of heavy and superheavy elements . In: Nuclear Physics, Section A . tape 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, DN Basu: Search for long lived heaviest nuclei beyond the valley of stability . In: Physical Review C (Nuclear Physics) . tape 77 , no. 4 , 2008, p. 044603-10 , doi : 10.1103 / PhysRevC.77.044603 , arxiv : 0802.3837v1 .
  4. ↑ P. R Chowdhury, C. Samanta, DN Basu: Nuclear half-lives for α-radioactivity of elements with 100 ≤ Z ≤ 130 . In: Atomic Data and Nuclear Data Tables . tape 94 , no. 6 , 2008, p. 781-806 , doi : 10.1016 / j.adt.2008.01.003 , arxiv : 0802.4161v2 .

Web links

Wiktionary: Ununennium  - explanations of meanings, word origins, synonyms, translations