Isotopes of oganesson

Last updated
Isotopes of oganesson  (118Og)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
294Og synth 0.7 ms [2] [3] α 290Lv
SF –

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 700 microseconds.

Contents

List of isotopes

Nuclide
 Z N Isotopic mass (Da)
[n 1] [n 2] 		Half-life
Decay
mode
[n 3] 		Daughter
isotope
Spin and
parity
294Og118176294.21392(71)#0.7(3) ms [4] α 290Lv 0+
SF (rare)(various)
This table header & footer:
  1. ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  2. ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  3. ↑ Modes of decay:
    SF: Spontaneous fission

Nucleosynthesis

Target-projectile combinations leading to Z=118 compound nuclei

The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with Z=118.[ citation needed ]

TargetProjectileCNAttempt result
208Pb86Kr294OgFailure to date
238U58Fe296OgReaction yet to be attempted
248Cm50Ti298OgFailure to date
250Cm50Ti300OgReaction yet to be attempted
249Cf48Ca297OgSuccessful reaction
250Cf48Ca298OgFailure to date
251Cf48Ca299OgFailure to date
252Cf48Ca300OgReaction yet to be attempted

Cold fusion

208Pb(86Kr,xn)294-xOg

In 1999, a team led by Victor Ninov at the Lawrence Berkeley National Laboratory performed this experiment, as a 1998 calculation by Robert Smolańczuk suggested a promising outcome. After eleven days of irradiation, three events of 293Og and its alpha decay products were reported in this reaction; this was the first reported discovery of element 118 and then-unknown element 116. [5]

The following year, they published a retraction after researchers at other laboratories were unable to duplicate the results and the Berkeley lab could not duplicate them either. [6] In June 2002, the director of the lab announced that the original claim of the discovery of these two elements had been based on data fabricated by principal author Victor Ninov. [7] [8] Newer experimental results and theoretical predictions have confirmed the exponential decrease in cross-sections with lead and bismuth targets as the atomic number of the resulting nuclide increases. [9]

Hot fusion

249Cf(48Ca,xn)297-xOg (x=3)

Following successful experiments utilizing calcium-48 projectiles and actinide targets to generate elements 114 and 116, [10] the search for element 118 was first performed at the Joint Institute for Nuclear Research (JINR) in 2002. One or two atoms of 294Og were produced in the 2002 experiment, and two more atoms were produced in a 2005 confirmation run. The discovery of element 118 was announced in 2006. [2]

Because of the very small fusion reaction probability (the fusion cross section is ~0.3–0.6  pb ), the experiment took four months and involved a beam dose of 2.5×1019 calcium ions that had to be shot at the californium target to produce the first recorded event believed to be the synthesis of oganesson. [11] Nevertheless, researchers were highly confident that the results were not a false positive; the chance that they were random events was estimated to be less than one part in 100,000. [12]

In a 2012 experiment aimed at the confirmation of tennessine, one alpha decay chain was attributed to 294Og. This synthesis event resulted from the population of 249Cf in the target as the decay product of the 249Bk target (half-life 330 days); the cross section and decays were consistent with previously reported observations of 294Og. [10]

From 1 October 2015 until 6 April 2016, the team at the JINR conducted a search for new isotopes of oganesson using a 48Ca beam and a target comprising a mixture of 249Cf (50.7%), 250Cf (12.9%), and 251Cf (36.4%). The experiment was performed at 252 MeV and 258 MeV beam energies. One event of 294Og was found at the lower beam energy, while no decays of oganesson isotopes were found at the higher beam energy; a cross section of 0.9 pb for the 249Cf(48Ca,3n) was estimated. [13]

250,251Cf(48Ca,xn)298,299-xOg

In the 2015–2016 experiment, these reactions were performed in a search for 295Og and 296Og. No events attributable to a reaction with the 250Cf or 251Cf portions of the target were found. A repeat of this experiment was planned for 2017–2018. [13]

248Cm(50Ti,xn)298-xOg

This reaction was originally planned to be tested at the JINR and RIKEN in 2017–2018, as it uses the same 50Ti projectile as planned experiments leading to elements 119 and 120. [14] A search beginning in summer 2016 at RIKEN for 295Og in the 3n channel of this reaction was unsuccessful, though the study is planned to resume; a detailed analysis and cross section limit were not provided. [15] [16]

Theoretical calculations

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 294Og, most likely 293Og, 295Og, 296Og, 297Og, 298Og, 300Og and 302Og. [17] [18] [19] Of these, 297Og might provide the best chances for obtaining longer-lived nuclei, [17] [19] and thus might become the focus of future work with this element. Some isotopes with many more neutrons, such as some located around 313Og, could also provide longer-lived nuclei. [20]

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; 2S = Two-step; σ = cross section

TargetProjectileCNChannel (product)σ maxModelRef
208Pb86Kr294Og1n (293Og)0.1 pbDNS [21]
208Pb85Kr293Og1n (292Og)0.18 pbDNS [21]
246Cm50Ti296Og3n (293Og)40 fb2S [22]
244Cm50Ti294Og2n (292Og)53 fb2S [22]
252Cf48Ca300Og3n (297Og)1.2 pbDNS [23]
251Cf48Ca299Og3n (296Og)1.2 pbDNS [23]
249Cf48Ca297Og3n (294Og)0.3 pbDNS [23]

Related Research Articles

Livermorium is a synthetic chemical element with the symbol Lv and has an atomic number of 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. Four isotopes of livermorium are known, with mass numbers between 290 and 293 inclusive; the longest-lived among them is livermorium-293 with a half-life of about 60 milliseconds. A fifth possible isotope with mass number 294 has been reported but not yet confirmed.

<span class="mw-page-title-main">Oganesson</span> Chemical element, symbol Og and atomic number 118

Oganesson is a synthetic chemical element with the symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research (JINR) in Dubna, near Moscow, Russia, by a joint team of Russian and American scientists. In December 2015, it was recognized as one of four new elements by the Joint Working Party of the international scientific bodies IUPAC and IUPAP. It was formally named on 28 November 2016. The name honors the nuclear physicist Yuri Oganessian, who played a leading role in the discovery of the heaviest elements in the periodic table. It is one of only two elements named after a person who was alive at the time of naming, the other being seaborgium, and the only element whose eponym is alive as of 2023.

<span class="mw-page-title-main">Island of stability</span> Predicted set of isotopes of relatively more stable superheavy elements

In nuclear physics, the island of stability is a predicted set of isotopes of superheavy elements that may have considerably longer half-lives than known isotopes of these elements. It is predicted to appear as an "island" in the chart of nuclides, separated from known stable and long-lived primordial radionuclides. Its theoretical existence is attributed to stabilizing effects of predicted "magic numbers" of protons and neutrons in the superheavy mass region.

Flerovium is a superheavy chemical element with symbol Fl and atomic number 114. It is an extremely radioactive synthetic element. It is 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.

<span class="mw-page-title-main">Nihonium</span> Chemical element, symbol Nh and atomic number 113

Nihonium is a synthetic chemical element with 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 the hypothetical chemical element in the periodic table with the placeholder symbol of 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).

Meitnerium (109Mt) 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 266Mt in 1982, and this is also the only isotope directly synthesized; all other isotopes are only known as decay products of heavier elements. There are eight known isotopes, from 266Mt to 278Mt. There may also be two isomers. The longest-lived of the known isotopes is 278Mt with a half-life of 8 seconds. The unconfirmed heavier 282Mt appears to have an even longer half-life of 67 seconds.

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.

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 6 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 seven known isotopes, and possibly 2 nuclear isomers. The longest-lived isotope is 289Fl with a half-life of 1.9 seconds, but the unconfirmed 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 an artificial 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 four known radioisotopes from 290Lv to 293Lv, as well as a few suggestive indications of a possible heavier isotope 294Lv. The longest-lived of the four well-characterised isotopes 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.

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

Unbinilium (120Ubn) has not yet been synthesised, so all data would be theoretical 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 the hypothetical chemical element with 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.

Unbiquadium, also known as element 124 or eka-uranium, is the hypothetical chemical element with atomic number 124 and placeholder symbol Ubq. Unbiquadium and Ubq are the temporary IUPAC name and symbol, respectively, until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table, unbiquadium is expected to be a g-block superactinide and the sixth element in the 8th period. Unbiquadium has attracted attention, as it may lie within the island of stability, leading to longer half-lives, especially for 308Ubq which is predicted to have a magic number of neutrons (184).

Unbihexium, also known as element 126 or eka-plutonium, is the hypothetical chemical element with atomic number 126 and placeholder symbol Ubh. Unbihexium and Ubh are the temporary IUPAC name and symbol, respectively, until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table, unbihexium is expected to be a g-block superactinide and the eighth element in the 8th period. Unbihexium has attracted attention among nuclear physicists, especially in early predictions targeting properties of superheavy elements, for 126 may be a magic number of protons near the center of an island of stability, leading to longer half-lives, especially for 310Ubh or 354Ubh which may also have magic numbers of neutrons.

References

  1. ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. 1 2 Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; et al. (2006-10-09). "Synthesis of the isotopes of elements 118 and 116 in the 249Cf and 245Cm+48Ca fusion reactions". Physical Review C. 74 (4): 044602. Bibcode:2006PhRvC..74d4602O. doi:10.1103/PhysRevC.74.044602 . Retrieved 2008-01-18.
  3. ↑ Oganessian, Yuri Ts.; Rykaczewski, Krzysztof P. (August 2015). "A beachhead on the island of stability". Physics Today. 68 (8): 32–38. Bibcode:2015PhT....68h..32O. doi:10.1063/PT.3.2880. OSTI   1337838.
  4. ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (1 March 2021). "The NUBASE2020 evaluation of nuclear physics properties *". Chinese Physics C, High Energy Physics and Nuclear Physics. 45 (3). doi: 10.1088/1674-1137/abddae . ISSN   1674-1137 . Retrieved 29 June 2023.
  5. ↑ Hoffman, D.C; Ghiorso, A.; Seaborg, G.T. (2000). The Transuranium People: The Inside Story. Imperial College Press. pp. 425–431. ISBN   978-1-86094-087-3.
  6. ↑ 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.
  7. ↑ Dalton, R. (2002). "Misconduct: The stars who fell to Earth". Nature . 420 (6917): 728–729. Bibcode:2002Natur.420..728D. doi:10.1038/420728a. PMID   12490902. S2CID   4398009.
  8. ↑ Element 118 disappears two years after it was discovered Archived 2007-10-12 at the Wayback Machine . Physicsworld.com. Retrieved on 2 April 2012.
  9. ↑ Zagrebaev, Valeriy; Karpov, Alexander; Greiner, Walter (2013). "Future of superheavy element research: Which nuclei could be synthesized within the next few years?" (PDF). Journal of Physics. 420 (1): 012001. arXiv: 1207.5700 . Bibcode:2013JPhCS.420a2001Z. doi:10.1088/1742-6596/420/1/012001. S2CID   55434734.
  10. 1 2 Oganessian, Y.T. (2015). "Super-heavy element research". Reports on Progress in Physics. 78 (3): 036301. Bibcode:2015RPPh...78c6301O. doi:10.1088/0034-4885/78/3/036301. PMID   25746203. S2CID   37779526.
  11. ↑ "Ununoctium". WebElements Periodic Table. Retrieved 2007-12-09.
  12. ↑ Jacoby, Mitch (17 October 2006). "Element 118 Detected, With Confidence". Chemical & Engineering News. 84 (43): 11. doi:10.1021/cen-v084n043.p011 . Retrieved 18 January 2008. I would say we're very confident.
  13. 1 2 Voinov, A.A.; et al. (2018). "Study of the 249-251Cf + 48Ca reactions: recent results and outlook". Journal of Physics: Conference Series. 966: 012057. doi: 10.1088/1742-6596/966/1/012057 .
  14. ↑ Roberto, J. B. (31 March 2015). "Actinide Targets for Super-Heavy Element Research" (PDF). cyclotron.tamu.edu. Texas A & M University. Retrieved 28 April 2017.
  15. ↑ Hauschild, K. (26 June 2019). Superheavy nuclei at RIKEN, Dubna, and JYFL (PDF). Conseil Scientifique de l'IN2P3. Retrieved 31 July 2019.
  16. ↑ Hauschild, K. (2019). Heavy nuclei at RIKEN, Dubna, and JYFL (PDF). Conseil Scientifique de l'IN2P3. Retrieved 1 August 2019.
  17. 1 2 P. Roy Chowdhury; C. Samanta; D. N. Basu (January 26, 2006). "α decay half-lives of new superheavy elements". Physical Review C. 73 (1): 014612. arXiv: nucl-th/0507054 . Bibcode:2006PhRvC..73a4612C. doi:10.1103/PhysRevC.73.014612. S2CID   118739116 . Retrieved 2008-01-18.
  18. ↑ C. Samanta; P. Roy Chowdhury; D. N. Basu (April 6, 2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nuclear Physics A. 789 (1–4): 142–154. arXiv: nucl-th/0703086 . Bibcode:2007NuPhA.789..142S. CiteSeerX   10.1.1.264.8177 . doi:10.1016/j.nuclphysa.2007.04.001. S2CID   7496348.
  19. 1 2 G. Royer; K. Zbiri; C. Bonilla (2004). "Entrance channels and alpha decay half-lives of the heaviest elements". Nuclear Physics A. 730 (3–4): 355–376. arXiv: nucl-th/0410048 . Bibcode:2004NuPhA.730..355R. doi:10.1016/j.nuclphysa.2003.11.010.
  20. ↑ S. B. Duarte; O. A. P. Tavares; M. Gonçalves; O. Rodríguez; F. Guzmán; T. N. Barbosa; F. García; A. Dimarco (2004). "Half-life predictions for decay modes of superheavy nuclei". Journal of Physics G: Nuclear and Particle Physics. 30 (10): 1487–1494. Bibcode:2004JPhG...30.1487D. CiteSeerX   10.1.1.692.3012 . doi:10.1088/0954-3899/30/10/014.
  21. 1 2 Feng, Zhao-Qing; Jin, Gen-Ming; Li, Jun-Qing; Scheid, Werner (2007). "Formation of superheavy nuclei in cold fusion reactions". Physical Review C. 76 (4): 044606. arXiv: 0707.2588 . Bibcode:2007PhRvC..76d4606F. doi:10.1103/PhysRevC.76.044606. S2CID   711489.
  22. 1 2 Liu, L.; Shen, C.; Li, Q.; Tu, Y.; Wang, X.; Wang, Y. (2016). "Residue cross sections of 50Ti-induced fusion reactions based on the two-step model". European Physical Journal A . 52 (35). arXiv: 1512.06504 . doi:10.1140/epja/i2016-16035-0. S2CID   254116073.
  23. 1 2 3 Feng, Z; Jin, G; Li, J; Scheid, W (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A. 816 (1–4): 33–51. arXiv: 0803.1117 . Bibcode:2009NuPhA.816...33F. doi:10.1016/j.nuclphysa.2008.11.003. S2CID   18647291.
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