Isotopes of ununennium

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Ununennium (119Uue) has not yet been synthesised, so there is no experimental data and a standard atomic weight cannot be given. Like all synthetic elements, it would have no stable isotopes.

Contents

List of isotopes

No isotopes of ununennium are known.

Nucleosynthesis

Target-projectile combinations leading to Z = 119 compound nuclei

The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with Z = 119. [1]

TargetProjectileCNAttempt result
208Pb87Rb295UueReaction yet to be attempted
209Bi86Kr295UueReaction yet to be attempted
238U59Co297UueReaction yet to be attempted
237Np58Fe295UueReaction yet to be attempted
244Pu55Mn299UueReaction yet to be attempted
243Am54Cr297Uue [2] Reaction yet to be attempted
248Cm51V299UueReaction being attempted
250Cm51V301UueReaction yet to be attempted
249Bk50Ti299UueFailure to date
249Cf45Sc294UueReaction yet to be attempted
254Es48Ca302UueFailure to date

Cold fusion

Following the claimed synthesis of 293Og in 1999 at the Lawrence Berkeley National Laboratory from 208Pb and 86Kr, the analogous reactions 209Bi + 86Kr and 208Pb + 87Rb were proposed for the synthesis of element 119 and its then-unknown alpha decay daughters, elements 117, 115, and 113. [3] The retraction of these results in 2001 [4] and more recent calculations on the cross sections for "cold" fusion reactions cast doubt on this possibility; for example, a maximum yield of 2 fb is predicted for the production of 294Uue in the former reaction. [5] Radioactive ion beams may provide an alternative method utilizing a lead or bismuth target, and may enable the production of more neutron-rich isotopes should they become available at required intensities. [5]

Hot fusion

243Am(54Cr,xn)297−xUue

There are indications that the team at the Joint Institute for Nuclear Research (JINR) in Russia plans to try this reaction in the future. The product of the 3n channel would be 294Uue; its expected granddaughter 286Mc was synthesised in a preparatory experiment at the JINR in 2021, using the reaction 243Am(48Ca,5n)286Mc. [2]

The team at the Heavy Ion Research Facility in Lanzhou (HIRFL), which is operated by the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences, also plans to try the 243Am+54Cr reaction. [6] [7]

248Cm(51V,xn)299−xUue

The team at RIKEN in Wakō, Japan began bombarding curium-248 targets with a vanadium-51 beam in January 2018 [8] to search for element 119. Curium was chosen as a target, rather than heavier berkelium or californium, as these heavier targets are difficult to prepare. [9] The reduced asymmetry of the reaction is expected to approximately halve the cross section, requiring a sensitivity "on the order of at least 30 fb". [10] The 248Cm targets were provided by Oak Ridge National Laboratory. RIKEN developed a high-intensity vanadium beam. [11] The experiment began at a cyclotron while RIKEN upgraded its linear accelerators; the upgrade was completed in 2020. [12] Bombardment may be continued with both machines until the first event is observed; the experiment is currently running intermittently for at least 100 days per year. [13] [9] The RIKEN team's efforts are being financed by the Emperor of Japan. [14]

248
96Cm
 + 51
23V
 → 299
119Uue
* → no atoms yet

The produced isotopes of ununennium are expected to undergo two alpha decays to known isotopes of moscovium (288Mc and 287Mc respectively), [8] which would anchor them to a known sequence of five further alpha decays and corroborate their production. In 2022, the optimal reaction energy for synthesis of ununennium in this reaction was experimentally estimated as 234.8±1.8 MeV at RIKEN. [15] The cross section is probably below 10 fb. [11]

As of September 2023, the team at RIKEN had run the 248Cm+51V reaction for 462 days. A report by the RIKEN Nishina Center Advisory Committee noted that this reaction was chosen because of the availability of the target and projectile materials, despite predictions favoring the 249Bk+50Ti reaction, owing to the 50Ti projectile being closer to doubly magic 48Ca and having an even atomic number (22); reactions with even-Z projectiles have generally been shown to have greater cross-sections. The report recommended that if the 5 fb cross-section limit is reached without any events observed, then the team should "evaluate and eventually reconsider the experimental strategy before taking additional beam time." [16] As of August 2024, the team at RIKEN was still running this reaction "24/7". [17]

249Bk(50Ti,xn)299−xUue

From April to September 2012, an attempt to synthesize the isotopes 295Uue and 296Uue was made by bombarding a target of berkelium-249 with titanium-50 at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. [18] [19] This reaction between 249Bk and 50Ti was predicted to be the most favorable practical reaction for formation of ununennium, [19] as it is rather asymmetrical, [20] though also somewhat cold. [21] (The reaction between 254Es and 48Ca would be superior, but preparing milligram quantities of 254Es for a target is difficult.) [20] Moreover, as berkelium-249 decays to californium-249 (the next element) with a short half-life of 327 days, this allowed elements 119 and 120 to be searched for simultaneously. [10] Nevertheless, the necessary change from the "silver bullet" 48Ca to 50Ti divides the expected yield of ununennium by about twenty, as the yield is strongly dependent on the asymmetry of the fusion reaction. [20] Due to the predicted short half-lives, the GSI team used new "fast" electronics capable of registering decay events within microseconds. [19] [20]

249
97Bk
 + 50
22Ti
 → 299
119Uue
* → no atoms
249
98Cf
 + 50
22Ti
 → 299
120Ubn
* → no atoms

Neither element 119 nor element 120 was observed. This implied a limiting cross-section of 65 fb for producing element 119 in these reactions, and 200 fb for element 120. [21] [10] The predicted actual cross section for producing element 119 in this reaction is around 40 fb, which is at the limits of current technology. [20] (The record lowest cross section of an experimentally successful reaction is 30 fb for the reaction between 209Bi and 70Zn producing nihonium.) [20] The experiment was originally planned to continue to November 2012, [22] but was stopped early to make use of the 249Bk target to confirm the synthesis of tennessine (thus changing the projectiles to 48Ca). [21]

The team at the Joint Institute for Nuclear Research in Dubna, Russia, planned to attempt this reaction. [23] [24] [25] [26] [27] [28]

254Es(48Ca,xn)302−xUue

The synthesis of ununennium was first attempted in 1985 by bombarding a sub-microgram target of einsteinium-254 with calcium-48 ions at the superHILAC accelerator at Berkeley, California:

254
99Es
 + 48
20Ca
 → 302
119Uue
* → no atoms

No atoms were identified, leading to a limiting cross section of 300 nb. [29] Later calculations suggest that the cross section of the 3n reaction (which would result in 299Uue and three neutrons as products) would actually be six hundred thousand times lower than this upper bound, at 0.5 pb. [30] Tens of milligrams of einsteinium, an amount that cannot presently be produced, would be needed for this reaction to have a reasonable chance of succeeding. [11]

Related Research Articles

Livermorium is a synthetic chemical element; it has symbol Lv and atomic number 116. It is an extremely radioactive element that has only been created in a laboratory setting and has not been observed in nature. The element is named after the Lawrence Livermore National Laboratory in the United States, which collaborated with the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, to discover livermorium during experiments conducted between 2000 and 2006. The name of the laboratory refers to the city of Livermore, California, where it is located, which in turn was named after the rancher and landowner Robert Livermore. The name was adopted by IUPAC on May 30, 2012. Six isotopes of livermorium are known, with mass numbers of 288–293 inclusive; the longest-lived among them is livermorium-293 with a half-life of about 80 milliseconds. A seventh possible isotope with mass number 294 has been reported but not yet confirmed.

Unbinilium, also known as eka-radium or element 120, is a hypothetical chemical element; it has symbol Ubn and atomic number 120. Unbinilium and Ubn are the temporary systematic IUPAC name and symbol, which are used until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table of the elements, it is expected to be an s-block element, an alkaline earth metal, and the second element in the eighth period. It has attracted attention because of some predictions that it may be in the island of stability.

Ununennium, also known as eka-francium or element 119, is a hypothetical chemical element; it has symbol Uue and atomic number 119. Ununennium and Uue are the temporary systematic IUPAC name and symbol respectively, which are used until the element has been discovered, confirmed, and a permanent name is decided upon. 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. It is the lightest element that has not yet been synthesized.

Moscovium is a synthetic chemical element; it has symbol Mc and atomic number 115. It was first synthesized in 2003 by a joint team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. In December 2015, it was recognized as one of four new elements by the Joint Working Party of international scientific bodies IUPAC and IUPAP. On 28 November 2016, it was officially named after the Moscow Oblast, in which the JINR is situated.

An extended periodic table theorizes about chemical elements beyond those currently known and proven. The element with the highest atomic number known is oganesson (Z = 118), which completes the seventh period (row) in the periodic table. All elements in the eighth period and beyond thus remain purely hypothetical.

Flerovium is a synthetic chemical element; it has symbol Fl and atomic number 114. It is an extremely radioactive, superheavy element, named after the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research in Dubna, Russia, where the element was discovered in 1999. The lab's name, in turn, honours Russian physicist Georgy Flyorov. IUPAC adopted the name on 30 May 2012. The name and symbol had previously been proposed for element 102 (nobelium), but was not accepted by IUPAC at that time.

Nihonium is a synthetic chemical element; it has the symbol Nh and atomic number 113. It is extremely radioactive: its most stable known isotope, nihonium-286, has a half-life of about 10 seconds. In the periodic table, nihonium is a transactinide element in the p-block. It is a member of period 7 and group 13.

Unbibium, also known as element 122 or eka-thorium, is a hypothetical chemical element; it has placeholder symbol Ubb and atomic number 122. Unbibium and Ubb are the temporary systematic IUPAC name and symbol respectively, which are used until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table of the elements, it is expected to follow unbiunium as the second element of the superactinides and the fourth element of the 8th period. Similarly to unbiunium, it is expected to fall within the range of the island of stability, potentially conferring additional stability on some isotopes, especially 306Ubb which is expected to have a magic number of neutrons (184).

Hassium (108Hs) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 265Hs in 1984. There are 13 known isotopes from 263Hs to 277Hs and up to six isomers. The most stable known isotope is 271Hs, with a half-life of about 46 seconds, though this assignment is not definite due to uncertainty arising from a low number of measurements. The isotopes 269Hs and 270Hs respectively have half-lives of about 12 seconds and 7.6 seconds. It is also possible that the isomer 277mHs is more stable than these, with a reported half-life 130±100 seconds, but only one event of decay of this isotope has been registered as of 2016.

Darmstadtium (110Ds) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 269Ds in 1994. There are 11 known radioisotopes from 267Ds to 281Ds and 2 or 3 known isomers. The longest-lived isotope is 281Ds with a half-life of 14 seconds. However, the unconfirmed 282Ds might have an even longer half-life of 67 seconds.

Roentgenium (111Rg) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 272Rg in 1994, which is also the only directly synthesized isotope; all others are decay products of heavier elements. There are seven known radioisotopes, having mass numbers of 272, 274, and 278–282. The longest-lived isotope is 282Rg with a half-life of about 2 minutes, although the unconfirmed 283Rg and 286Rg may have longer half-lives of about 5.1 minutes and 10.7 minutes respectively.

Copernicium (112Cn) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 277Cn in 1996. There are seven known radioisotopes ; the longest-lived isotope is 285Cn with a half-life of 30 seconds.

Nihonium (113Nh) is a synthetic element. Being synthetic, a standard atomic weight cannot be given and like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 284Nh as a decay product of 288Mc in 2003. The first isotope to be directly synthesized was 278Nh in 2004. There are 6 known radioisotopes from 278Nh to 286Nh, along with the unconfirmed 287Nh and 290Nh. The longest-lived isotope is 286Nh with a half-life of 9.5 seconds.

Flerovium (114Fl) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 289Fl in 1999. Flerovium has six known isotopes, along with the unconfirmed 290Fl, and possibly two nuclear isomers. The longest-lived isotope is 289Fl with a half-life of 1.9 seconds, but 290Fl may have a longer half-life of 19 seconds.

Moscovium (115Mc) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no known stable isotopes. The first isotope to be synthesized was 288Mc in 2004. There are five known radioisotopes from 286Mc to 290Mc. The longest-lived isotope is 290Mc with a half-life of 0.65 seconds.

Livermorium (116Lv) is a synthetic element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 293Lv in 2000. There are six known radioisotopes, with mass numbers 288–293, as well as a few suggestive indications of a possible heavier isotope 294Lv. The longest-lived known isotope is 293Lv with a half-life of 53 ms.

Tennessine (117Ts) is the most-recently synthesized synthetic element, and much of the data is hypothetical. As for any synthetic element, a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotopes to be synthesized were 293Ts and 294Ts in 2009. The longer-lived isotope is 294Ts with a half-life of 51 ms.

Oganesson (118Og) is a synthetic element created in particle accelerators, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first and only isotope to be synthesized was 294Og in 2002 and 2005; it has a half-life of 0.7 milliseconds.

Unbinilium (120Ubn) has not yet been synthesised, so there is no experimental data and a standard atomic weight cannot be given. Like all synthetic elements, it would have no stable isotopes.

Unbiunium, also known as eka-actinium or element 121, is a hypothetical chemical element; it has symbol Ubu and atomic number 121. Unbiunium and Ubu are the temporary systematic IUPAC name and symbol respectively, which are used until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table of the elements, it is expected to be the first of the superactinides, and the third element in the eighth period. It has attracted attention because of some predictions that it may be in the island of stability. It is also likely to be the first of a new g-block of elements.

References

  1. ↑ Isospin dependence in heavy-element synthesis in fusion-evaporation reactions with neutron-rich radioactive ion-beams, A. Yakushev et al.
  2. 1 2 "Superheavy Element Factory: overview of obtained results". Joint Institute for Nuclear Research. 24 August 2023. Retrieved 7 December 2023.
  3. ↑ Hoffman, Ghiorso & Seaborg 2000, p. 431.
  4. ↑ Public Affairs Department (21 July 2001). "Results of element 118 experiment retracted". Berkeley Lab. Archived from the original on 29 January 2008. Retrieved 18 January 2008.
  5. 1 2 Loveland, W. (2007). "Synthesis of transactinide nuclei using radioactive beams" (PDF). Physical Review C. 76 (1). 014612. Bibcode:2007PhRvC..76a4612L. doi:10.1103/PhysRevC.76.014612.
  6. ↑ Geng, Chang; Chen, Peng-Hui; Niu, Fei; Yang, Zu-Xing; Zeng, Xiang-Hua; Feng, Zhao-Qing (23 February 2024). "Assessing the Impact of Nuclear Mass Models on the Prediction of Synthesis Cross Sections for Superheavy Elements". arXiv: 2402.15304v1 [nucl-th].
  7. ↑ Gan, Z. G.; Huang, W. X.; Zhang, Z. Y.; Zhou, X. H.; Xu, H. S. (2022). "Results and perspectives for study of heavy and super-heavy nuclei and elements at IMP/CAS". The European Physical Journal A. 58 (158). doi:10.1140/epja/s10050-022-00811-w.
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  12. ↑ Sakurai, Hiroyoshi (1 April 2020). "Greeting | RIKEN Nishina Center". With the completion of the upgrade of the linear accelerator and BigRIPS at the beginning of 2020, the RNC aims to synthesize new elements from element 119 and beyond.
  13. ↑ Ball, P. (2019). "Extreme chemistry: experiments at the edge of the periodic table" (PDF). Nature. 565 (7741): 552–555. Bibcode:2019Natur.565..552B. doi: 10.1038/d41586-019-00285-9 . ISSN   1476-4687. PMID   30700884. S2CID   59524524. We started the search for element 119 last June," says RIKEN researcher Hideto En'yo. "It will certainly take a long time — years and years — so we will continue the same experiment intermittently for 100 or more days per year, until we or somebody else discovers it.
  14. ↑ Chapman, Kit; Turner, Kristy (13 February 2018). "The hunt is on". Education in Chemistry. Royal Society of Chemistry. Retrieved 28 June 2019. The hunt for element 113 was almost abandoned because of lack of resources, but this time Japan's emperor is bankrolling Riken's efforts to extend the periodic table to its eighth row.
  15. ↑ Tanaka, Masaomi; Brionnet, Pierre; Du, Miting; et al. (2022). "Probing Optimal Reaction Energy for Synthesis of Element 119 from 51V+248Cm Reaction with Quasielastic Barrier Distribution Measurement". Journal of the Physical Society of Japan. 91 (8): 042081–1–11. Bibcode:2022JPSJ...91h4201T. doi: 10.7566/JPSJ.91.084201 . S2CID   250399446.
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  18. ↑ Modern alchemy: Turning a line, The Economist, May 12, 2012.
  19. 1 2 3 DÜLLMANN, CHRISTOPH E. (2013). "Superheavy Element Research at Tasca at Gsi". Fission and Properties of Neutron-Rich Nuclei. WORLD SCIENTIFIC: 271–277. doi:10.1142/9789814525435_0029. ISBN   978-981-4525-42-8 . Retrieved 21 March 2022.
  20. 1 2 3 4 5 6 Zagrebaev, Karpov & Greiner 2013.
  21. 1 2 3 "Superheavy Element Research at TASCA" (PDF).
  22. ↑ "Search for element 119: Christoph E. Düllmann for the TASCA E119 collaboration" (PDF). Archived from the original (PDF) on 2016-03-04. Retrieved 2015-09-15.
  23. ↑ "Scientists will begin experiments on the synthesis of element 119 in 2019". jinr.ru. JINR. 28 September 2016. Retrieved 31 March 2017. "The discovery of elements 115, 117 and 118 is an accomplished fact; they were placed in the periodic table, though still unnamed and will be confirmed only at the end of the year. The D.I.Mendeleev Periodic Table is not infinite. In 2019, scientists will begin the synthesis of elements 119 and 120 which are the first in the 8th period," said S.N. Dmitriev.
  24. ↑ Dmitriev, Sergey; Itkis, Mikhail; Oganessian, Yuri (2016). Status and perspectives of the Dubna superheavy element factory (PDF). Nobel Symposium NS160 – Chemistry and Physics of Heavy and Superheavy Elements. doi: 10.1051/epjconf/201613108001 .
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  27. ↑ Morita, Kōsuke (5 February 2016). "The Discovery of Element 113". Archived from the original on 2021-11-18. Retrieved 28 April 2017– via YouTube.
  28. ↑ Morimoto, Kouji (2016). The discovery of element 113 at RIKEN (PDF). 26th International Nuclear Physics Conference. Retrieved 14 May 2017.
  29. ↑ Lougheed, R.; Landrum, J.; Hulet, E.; et al. (3 June 1985). "Search for superheavy elements using the 48Ca + 254Esg reaction" . Physical Review C. 32 (5) (published 1 November 1985): 1760–1763. Bibcode:1985PhRvC..32.1760L. doi:10.1103/PhysRevC.32.1760. PMID   9953034 . Retrieved 21 March 2022.
  30. ↑ Feng, Z.; Jin, G.; Li, J.; Scheid, W. (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A. 816 (1): 33. arXiv: 0803.1117 . Bibcode:2009NuPhA.816...33F. doi:10.1016/j.nuclphysa.2008.11.003. S2CID   18647291.

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