Isotopes of unbinilium

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.

List of isotopes

No isotopes of unbinilium are known.

Nucleosynthesis

Target-projectile combinations leading to Z = 120 compound nuclei

The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with Z = 120. ^[1]

Target	Projectile	CN	Attempt result
208Pb	88Sr	296Ubn	Reaction yet to be attempted
238U	64Ni	302Ubn	Failure to date
237Np	59Co	296Ubn	Reaction yet to be attempted
244Pu	58Fe	302Ubn	Failure to date
244Pu	60Fe	304Ubn	Reaction yet to be attempted
243Am	55Mn	298Ubn	Reaction yet to be attempted
245Cm	54Cr	299Ubn [2]	Reaction yet to be attempted
246Cm	54Cr	300Ubn [3]	Reaction yet to be attempted
248Cm	54Cr	302Ubn	Failure to date
250Cm	54Cr	304Ubn	Reaction yet to be attempted
249Bk	51V	300Ubn	Reaction yet to be attempted
249Cf	50Ti	299Ubn	Failure to date
250Cf	50Ti	300Ubn	Reaction yet to be attempted
251Cf	50Ti	301Ubn	Reaction yet to be attempted
252Cf	50Ti	302Ubn	Reaction yet to be attempted
257Fm	48Ca	305Ubn	Reaction yet to be attempted

Hot fusion

²³⁸U(⁶⁴Ni,xn)^302-xUbn

In April 2007, the team at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany attempted to create unbinilium using a ²³⁸ U target and a ⁶⁴ Ni beam: ^[4]

²³⁸
₉₂U
+ ⁶⁴
₂₈Ni
→ ³⁰²
₁₂₀Ubn
* → no atoms

No atoms were detected, providing a limit of 1.6  pb for the cross section at the energy provided. The GSI repeated the experiment with higher sensitivity in three separate runs in April–May 2007, January–March 2008, and September–October 2008, all with negative results, reaching a cross section limit of 90 fb. ^[4]

²⁴⁴Pu(⁵⁸Fe,xn)^302-xUbn

Following their success in obtaining oganesson by the reaction between ²⁴⁹Cf and ⁴⁸Ca in 2006, the team at the Joint Institute for Nuclear Research (JINR) in Dubna started experiments in March–April 2007 to attempt to create unbinilium with a ⁵⁸Fe beam and a ²⁴⁴Pu target. ^{[5] [6]} Initial analysis revealed that no atoms of unbinilium were produced, providing a limit of 400  fb for the cross section at the energy studied. ^[7]

²⁴⁴
₉₄Pu
+ ⁵⁸
₂₆Fe
→ ³⁰²
₁₂₀Ubn
* → no atoms

The Russian team planned to upgrade their facilities before attempting the reaction again. ^[7]

²⁴⁵Cm(⁵⁴Cr,xn)^299-xUbn

There are indications that this reaction may be tried by the JINR in the future. The expected products of the 3n and 4n channels, ²⁹⁶Ubn and ²⁹⁵Ubn, could undergo five alpha decays to reach the darmstadtium isotopes ²⁷⁶Ds and ²⁷⁵Ds respectively; these darmstadtium isotopes were synthesised at the JINR in 2022 and 2023 respectively, both in the ²³²Th+⁴⁸Ca reaction. ^{[2] [8]}

²⁴⁸Cm(⁵⁴Cr,xn)^302-xUbn

In 2011, after upgrading their equipment to allow the use of more radioactive targets, scientists at the GSI attempted the rather asymmetrical fusion reaction: ^[9]

²⁴⁸
₉₆Cm
+ ⁵⁴
₂₄Cr
→ ³⁰²
₁₂₀Ubn
* → no atoms

It was expected that the change in reaction would quintuple the probability of synthesizing unbinilium, ^[10] as the yield of such reactions is strongly dependent on their asymmetry. ^[11] Although this reaction is less asymmetric than the ²⁴⁹Cf+⁵⁰Ti reaction, it also creates more neutron-rich unbinilium isotopes that should receive increased stability from their proximity to the shell closure at N = 184. ^[12] Three signals were observed in May 2011; a possible assignment to ²⁹⁹Ubn and its daughters was considered, ^[13] but could not be confirmed, ^{[14] [15] [12]} and a different analysis suggested that what was observed was simply a random sequence of events. ^[16]

In March 2022, Yuri Oganessian gave a seminar at the JINR considering how one could synthesise element 120 in the ²⁴⁸Cm+⁵⁴Cr reaction. ^[17] In 2023, the director of the JINR, Grigory Trubnikov, stated that he hoped that the experiments to synthesise element 120 will begin in 2025. ^[18]

²⁴⁹Cf(⁵⁰Ti,xn)^299-xUbn

In August–October 2011, a different team at the GSI using the TASCA facility tried a new, even more asymmetrical reaction: ^{[9] [19]}

²⁴⁹
₉₈Cf
+ ⁵⁰
₂₂Ti
→ ²⁹⁹
₁₂₀Ubn
* → no atoms

Because of its asymmetry, ^[20] the reaction between ²⁴⁹Cf and ⁵⁰Ti was predicted to be the most favorable practical reaction for synthesizing unbinilium, although it is also somewhat cold, and is further away from the neutron shell closure at N = 184 than any of the other three reactions attempted. No unbinilium atoms were identified, implying a limiting cross section of 200 fb. ^[19] Jens Volker Kratz predicted the actual maximum cross section for producing unbinilium by any of the four reactions ²³⁸U+⁶⁴Ni, ²⁴⁴Pu+⁵⁸Fe, ²⁴⁸Cm+⁵⁴Cr, or ²⁴⁹Cf+⁵⁰Ti to be around 0.1 fb; ^[21] in comparison, the world record for the smallest cross section of a successful reaction was 30 fb for the reaction ²⁰⁹Bi(⁷⁰Zn,n)²⁷⁸ Nh, ^[11] and Kratz predicted a maximum cross section of 20 fb for producing ununennium. ^[21] If these predictions are accurate, then synthesizing ununennium would be at the limits of current technology, and synthesizing unbinilium would require new methods. ^[21]

This reaction was investigated again in April to September 2012 at the GSI. This experiment used a ²⁴⁹Bk target and a ⁵⁰Ti beam to produce element 119, but since ²⁴⁹Bk decays to ²⁴⁹Cf with a half-life of about 327 days, both elements 119 and 120 could be searched for simultaneously:

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. ^[22]

In May 2021, the JINR announced plans to investigate the ²⁴⁹Cf+⁵⁰Ti reaction in their new facility. ^[23] The ²⁴⁹Cf target would have been produced by the Oak Ridge National Laboratory in Oak Ridge, Tennessee, United States; the ⁵⁰Ti beam would be produced by the Hubert Curien Pluridisciplinary Institute in Strasbourg, Alsace, France. ^[24] However, after the Russian invasion of Ukraine began in 2022, collaboration between the JINR and other institutes completely ceased due to sanctions. ^[25] Thus, the JINR's plans have since shifted to the ²⁴⁸Cm+⁵⁴Cr reaction, where the target and projectile beam could both be made in Russia. ^{[24] [26]}

Starting from 2022, ^[27] plans began to be made to use the 88-inch cyclotron in the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California, United States to attempt to make new elements using ⁵⁰Ti projectiles. The plan was to first test them on a plutonium target to create livermorium (element 116), which was successful in 2024. Thus, an attempt to make element 120 in the ²⁴⁹Cf+⁵⁰Ti reaction is now planned for 2025. ^{[28] [29]}

References

1. Isospin dependence in heavy-element synthesis in fusion-evaporation reactions with neutron-rich radioactive ion-beams, A. Yakushev et al.
2. "Superheavy Element Factory: overview of obtained results". Joint Institute for Nuclear Research. 24 August 2023. Retrieved 7 December 2023.
3. https://indico.jinr.ru/event/3379/contributions/18435/attachments/14603/24496/11.2.%20133_SC_PAC_NP.pdf ^{[ bare URL PDF ]}
4. Hoffman, S.; et al. (2008). Probing shell effects at Z = 120 and N = 184 (Report). GSI Scientific Report. p. 131.
5. "A New Block on the Periodic Table" (PDF). Lawrence Livermore National Laboratory. April 2007. Retrieved 2008-01-18.
6. Itkis, M. G.; Oganessian, Yu. Ts. (2007). "Synthesis of New Nuclei and Study of Nuclear Properties and Heavy-Ion Reaction Mechanisms". jinr.ru. Joint Institute for Nuclear Research. Retrieved 23 September 2016.
7. Oganessian, Yu. Ts.; Utyonkov, V.; Lobanov, Yu.; et al. (2009). "Attempt to produce element 120 in the ²⁴⁴Pu+⁵⁸Fe reaction". Phys. Rev. C. 79 (2). 024603. Bibcode:2009PhRvC..79b4603O. doi:10.1103/PhysRevC.79.024603.
8. "New darmstadtium isotope discovered at Superheavy Element Factory". Joint Institute for Nuclear Research. 27 February 2023. Retrieved 29 March 2023.
9. Düllmann, C. E. (20 October 2011). "Superheavy Element Research: News from GSI and Mainz" . Retrieved 23 September 2016.
10. GSI (5 April 2012). "Searching for the island of stability". www.gsi.de. GSI. Retrieved 23 September 2016.
11. Zagrebaev, Karpov & Greiner 2013.
12. Hofmann, S.; Heinz, S.; Mann, R.; et al. (2016). "Review of even element super-heavy nuclei and search for element 120". The European Physical Journal A. 2016 (52): 180. Bibcode:2016EPJA...52..180H. doi:10.1140/epja/i2016-16180-4. S2CID   124362890.
13. Hofmann, S.; Heinz, S.; Mann, R.; et al. (2016). "Remarks on the Fission Barriers of SHN and Search for Element 120". In Peninozhkevich, Yu. E.; Sobolev, Yu. G. (eds.). Exotic Nuclei: EXON-2016 Proceedings of the International Symposium on Exotic Nuclei. Exotic Nuclei. pp. 155–164. ISBN   9789813226555.
14. Adcock, Colin (2 October 2015). "Weighty matters: Sigurd Hofmann on the heaviest of nuclei". JPhys+. Journal of Physics G: Nuclear and Particle Physics. Archived from the original on 18 July 2023. Retrieved 23 September 2016.
15. Hofmann, Sigurd (August 2015). "Search for Isotopes of Element 120 on the Island of SHN". Exotic Nuclei: 213–224. Bibcode:2015exon.conf..213H. doi:10.1142/9789814699464_0023. ISBN   978-981-4699-45-7.
16. Heßberger, F. P.; Ackermann, D. (2017). "Some critical remarks on a sequence of events interpreted to possibly originate from a decay chain of an element 120 isotope". The European Physical Journal A. 53 (123): 123. Bibcode:2017EPJA...53..123H. doi:10.1140/epja/i2017-12307-5. S2CID   125886824.
17. JINR (29 March 2022). "At seminar on synthesis of element 120". jinr.ru. JINR. Retrieved 17 April 2022.
18. Mayer, Anastasiya (31 May 2023). ""Большинство наших партнеров гораздо мудрее политиков"" ["Most of our partners are much wiser than politicians"]. Vedomosti (in Russian). Retrieved 15 August 2023. В этом году мы фактически завершаем подготовительную серию экспериментов по отладке всех режимов ускорителя и масс-спектрометров для синтеза 120-го элемента. Научились получать высокие интенсивности ускоренного хрома и титана. Научились детектировать сверхтяжелые одиночные атомы в реакциях с минимальным сечением. Теперь ждем, когда закончится наработка материала для мишени на реакторах и сепараторах у наших партнеров в «Росатоме» и в США: кюрий, берклий, калифорний. Надеюсь, что в 2025 г. мы полноценно приступим к синтезу 120-го элемента.
19. Yakushev, A. (2012). "Superheavy Element Research at TASCA" (PDF). asrc.jaea.go.jp. Retrieved 23 September 2016.
20. Siwek-Wilczyńska, K.; Cap, T.; Wilczyński, J. (April 2010). "How can one synthesize the element Z = 120?". International Journal of Modern Physics E. 19 (4): 500. Bibcode:2010IJMPE..19..500S. doi:10.1142/S021830131001490X.
21. Kratz, J. V. (5 September 2011). The Impact of Superheavy Elements on the Chemical and Physical Sciences (PDF). 4th International Conference on the Chemistry and Physics of the Transactinide Elements. Retrieved 27 August 2013.
22. Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; et al. (December 2020). "Search for elements 119 and 120" (PDF). Physical Review C. 102 (6): 064602. Bibcode:2020PhRvC.102f4602K. doi:10.1103/PhysRevC.102.064602. hdl:1885/289860. S2CID   229401931 . Retrieved 25 January 2021.
23. Sokolova, Svetlana; Popeko, Andrei (24 May 2021). "How are new chemical elements born?". jinr.ru. JINR. Retrieved 4 November 2021. Previously, we worked mainly with calcium. This is element 20 in the Periodic Table. It was used to bombard the target. And the heaviest element that can be used to make a target is californium, 98. Accordingly, 98 + 20 is 118. That is, to get element 120, we need to proceed to the next particle. This is most likely titanium: 22 + 98 = 120.
    
    There is still much work to adjust the system. I don't want to get ahead of myself, but if we can successfully conduct all the model experiments, then the first experiments on the synthesis of element 120 will probably start this year.
24. Riegert, Marion (19 July 2021). "In search of element 120 in the periodic table of elements". en.unistra.fr. University of Strasbourg . Retrieved 20 February 2022.
25. Ahuja, Anjana (18 October 2023). "Even the periodic table must bow to the reality of war". Financial Times. Retrieved 20 October 2023.
26. "В ЛЯР ОИЯИ впервые в мире синтезирован ливерморий-288" [Livermorium-288 was synthesized for the first time in the world at FLNR JINR] (in Russian). Joint Institute for Nuclear Research. 23 October 2023. Retrieved 18 November 2023.
27. Gates, J.; Pore, J.; Crawford, H.; Shaughnessy, D.; Stoyer, M. A. (25 October 2022). "The Status and Ambitions of the US Heavy Element Program". osti.gov. doi:10.2172/1896856. OSTI   1896856. S2CID   253391052 . Retrieved 13 November 2022.
28. Chapman, Kit (10 October 2023). "Berkeley Lab to lead US hunt for element 120 after breakdown of collaboration with Russia". Chemistry World. Retrieved 20 October 2023.
29. Biron, Lauren (16 October 2023). "Berkeley Lab to Test New Approach to Making Superheavy Elements". lbl.gov. Lawrence Berkeley National Laboratory . Retrieved 20 October 2023.

Sources

• Zagrebaev, V.; Karpov, A.; Greiner, W. (2013). "Future of superheavy element research: Which nuclei could be synthesized within the next few years?" (PDF). Journal of Physics: Conference Series . 420 (1). 012001. arXiv: 1207.5700 . Bibcode:2013JPhCS.420a2001Z. doi:10.1088/1742-6596/420/1/012001. ISSN   1742-6588. S2CID   55434734.