Isotopes of nihonium

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.

Isotopes of nihonium (₁₁₃Nh)

Main isotopes^[1] Decay abun­dance half-life (t1/2) mode pro­duct ^278Nh synth 0.002 s α ^274Rg ^282Nh synth 0.061 s α ^278Rg ^283Nh synth 0.123 s α ^279Rg ^284Nh synth 0.90 s α ^280Rg ε ^284Cn ^285Nh synth 2.1 s α ^281Rg SF – ^286Nh synth 9.5 s α ^282Rg ^287Nh synth 5.5 s?^[2] α ^283Rg ^290Nh synth 2 s?^[3] α ^286Rg

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List of isotopes

Nuclide	Z	N	Isotopic mass (Da) ^[n 1]^[n 2]	Half-life	Decay mode ^[n 3]	Daughter isotope	Spin and parity
^278Nh^[4]	113	165	278.17058(20)#	2.0+2.7 −0.7 ms	α	^274Rg
^282Nh	113	169	282.17567(39)#	61+73 −22 ms^[5]	α	^278Rg
^283Nh^[n 4]	113	170	283.17657(52)#	123+80 −35 ms^[5]	α	^279Rg
^284Nh^[n 5]	113	171	284.17873(62)#	0.90+0.07 −0.06 s^[5]	α (≥99%)	^280Rg
					EC (≤1%)^[5]	^284Cn
^285Nh^[n 6]	113	172	285.17973(89)#	2.1+0.6 −0.3 s^[5]	α (82%)	^281Rg
					SF (18%)^[5]	(various)
^286Nh^[n 7]	113	173	286.18221(72)#	9.5 s	α	^282Rg
^287Nh^[n 8]	113	174	287.18339(81)#	5.5 s	α	^283Rg
^290Nh^[n 9]	113	177		2 s?	α	^286Rg
This table header & footer: view

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:

   EC:	Electron capture

4. Not directly synthesized, occurs as decay product of ²⁸⁷Mc
5. Not directly synthesized, occurs as decay product of ²⁸⁸Mc
6. Not directly synthesized, occurs in decay chain of ²⁹³Ts
7. Not directly synthesized, occurs in decay chain of ²⁹⁴Ts
8. Not directly synthesized, occurs in decay chain of ²⁸⁷Fl; unconfirmed
9. Not directly synthesized, occurs in decay chain of ²⁹⁰Fl and ²⁹⁴Lv; unconfirmed

Isotopes and nuclear properties

Nucleosynthesis

Super-heavy elements such as nihonium are produced by bombarding lighter elements in particle accelerators that induce fusion reactions. Whereas most of the isotopes of nihonium can be synthesized directly this way, some heavier ones have only been observed as decay products of elements with higher atomic numbers.^[6]

Depending on the energies involved, the former are separated into "hot" and "cold". In hot fusion reactions, very light, high-energy projectiles are accelerated toward very heavy targets (actinides), giving rise to compound nuclei at high excitation energy (~40–50 MeV) that may either fission or evaporate several (3 to 5) neutrons.^[7] In cold fusion reactions, the produced fused nuclei have a relatively low excitation energy (~10–20 MeV), which decreases the probability that these products will undergo fission reactions. As the fused nuclei cool to the ground state, they require emission of only one or two neutrons, and thus, allows for the generation of more neutron-rich products.^[6] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).^[8]

Cold fusion

Before the synthesis of nihonium by the RIKEN team, scientists at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung) in Darmstadt, Germany also tried to synthesize nihonium by bombarding bismuth-209 with zinc-70 in 1998. No nihonium atoms were identified in two separate runs of the reaction.^[9] They repeated the experiment in 2003 again without success.^[9] In late 2003, the emerging team at RIKEN using their efficient apparatus GARIS attempted the reaction and reached a limit of 140 fb. In December 2003 – August 2004, they resorted to "brute force" and carried out the reaction for a period of eight months. They were able to detect a single atom of ²⁷⁸Nh.^[10] They repeated the reaction in several runs in 2005 and were able to synthesize a second atom,^[11] followed by a third in 2012.^[12]

The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=113.

Target	Projectile	CN	Attempt result
^208Pb	^71Ga	^279Nh	Reaction yet to be attempted
^209Bi	^70Zn	^279Nh	Successful reaction
^238U	^45Sc	^283Nh	Reaction yet to be attempted
^237Np	^48Ca	^285Nh	Successful reaction
^244Pu	^41K	^285Nh	Reaction yet to be attempted
^250Cm	^37Cl	^287Nh	Reaction yet to be attempted
^248Cm	^37Cl	^285Nh	Reaction yet to be attempted

Hot fusion

In June 2006, the Dubna-Livermore team synthesised nihonium directly by bombarding a neptunium-237 target with accelerated calcium-48 nuclei, in a search for the lighter isotopes ²⁸¹Nh and ²⁸²Nh and their decay products, to provide insight into the stabilizing effects of the closed neutron shells at N = 162 and N = 184:^[13]

²³⁷
₉₃Np
+ ⁴⁸
₂₀Ca
→ ²⁸²
₁₁₃Nh
+ 3 ¹
₀n

Two atoms of ²⁸²Nh were detected.^[13]

As decay product

List of nihonium isotopes observed by decay

Evaporation residue	Observed nihonium isotope
^294Lv, ^290Fl ?	^290Nh ?^[3]
^287Fl ?	^287Nh ?^[14]
^294Ts, ^290Mc	^286Nh^[15]
^293Ts, ^289Mc	^285Nh^[15]
^288Mc	^284Nh^[16]
^287Mc	^283Nh^[16]
^286Mc	^282Nh

Nihonium has been observed as a decay product of moscovium (via alpha decay). Moscovium currently has five known isotopes; all of them undergo alpha decays to become nihonium nuclei, with mass numbers between 282 and 286. Parent moscovium nuclei can be themselves decay products of tennessine. It may also occur as a decay product of flerovium (via electron capture), and parent flerovium nuclei can be themselves decay products of livermorium.^[17] For example, in January 2010, the Dubna team (JINR) identified nihonium-286 as a product in the decay of tennessine via an alpha decay sequence:^[15]

²⁹⁴
₁₁₇Ts
→ ²⁹⁰
₁₁₅Mc
+ ⁴
₂He

²⁹⁰
₁₁₅Mc
→ ²⁸⁶
₁₁₃Nh
+ ⁴
₂He

Theoretical calculations

Evaporation residue 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; σ = cross section

Target	Projectile	CN	Channel (product)	σmax	Model	Ref
^209Bi	^70Zn	^279Nh	1n (^278Nh)	30 fb	DNS	^[18]
^238U	^45Sc	^283Nh	3n (^280Nh)	20 fb	DNS	^[19]
^237Np	^48Ca	^285Nh	3n (^282Nh)	0.4 pb	DNS	^[20]
^244Pu	^41K	^285Nh	3n (^282Nh)	42.2 fb	DNS	^[19]
^250Cm	^37Cl	^287Nh	4n (^283Nh)	0.594 pb	DNS	^[19]
^248Cm	^37Cl	^285Nh	3n (^282Nh)	0.26 pb	DNS	^[19]

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. Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Münzenberg, G.; Antalic, S.; Barth, W.; 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.
3. Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Münzenberg, G.; Antalic, S.; Barth, W.; et al. (2016). "Review of even element super-heavy nuclei and search for element 120". The European Physics Journal A. 2016 (52). doi:10.1140/epja/i2016-16180-4.
4. Morita, Kosuke; Morimoto, Kouji; Kaji, Daiya; Haba, Hiromitsu; Ozeki, Kazutaka; Kudou, Yuki; Sumita, Takayuki; Wakabayashi, Yasuo; Yoneda, Akira; Tanaka, Kengo; Yamaki, Sayaka; Sakai, Ryutaro; Akiyama, Takahiro; Goto, Shin-ichi; Hasebe, Hiroo; Huang, Minghui; Huang, Tianheng; Ideguchi, Eiji; Kasamatsu, Yoshitaka; Katori, Kenji; Kariya, Yoshiki; Kikunaga, Hidetoshi; Koura, Hiroyuki; Kudo, Hisaaki; Mashiko, Akihiro; Mayama, Keita; Mitsuoka, Shin-ichi; Moriya, Toru; Murakami, Masashi; Murayama, Hirohumi; Namai, Saori; Ozawa, Akira; Sato, Nozomi; Sueki, Keisuke; Takeyama, Mirei; Tokanai, Fuyuki; Yamaguchi, Takayuki; Yoshida, Atsushi (15 October 2012). "New Result in the Production and Decay of an Isotope, 278 113, of the 113th Element". Journal of the Physical Society of Japan. 81 (10): 103201. arXiv:1209.6431. Bibcode:2012JPSJ...81j3201M. doi:10.1143/JPSJ.81.103201. ISSN 0031-9015. S2CID 119217928. Retrieved 29 June 2023.
5. Oganessian, Yu. Ts.; Utyonkov, V. K.; Kovrizhnykh, N. D.; et al. (2022). "New isotope ²⁸⁶Mc produced in the ²⁴³Am+⁴⁸Ca reaction". Physical Review C. 106 (64306): 064306. Bibcode:2022PhRvC.106f4306O. doi:10.1103/PhysRevC.106.064306. S2CID 254435744.
6. Armbruster, Peter & Münzenberg, Gottfried (1989). "Creating superheavy elements". Scientific American. 34: 36–42.
7. Barber, Robert C.; Gäggeler, Heinz W.; Karol, Paul J.; Nakahara, Hiromichi; Vardaci, Emanuele; Vogt, Erich (2009). "Discovery of the element with atomic number 112 (IUPAC Technical Report)". Pure and Applied Chemistry. 81 (7): 1331. doi:10.1351/PAC-REP-08-03-05.
8. Fleischmann, Martin; Pons, Stanley (1989). "Electrochemically induced nuclear fusion of deuterium". Journal of Electroanalytical Chemistry and Interfacial Electrochemistry. 261 (2): 301–308. doi:10.1016/0022-0728(89)80006-3.
9. "Search for element 113" 2012-02-19 at the Wayback Machine, Hofmann et al., GSI report 2003. Retrieved on 3 March 2008
10. Morita, Kosuke; Morimoto, Kouji; Kaji, Daiya; Akiyama, Takahiro; Goto, Sin-Ichi; Haba, Hiromitsu; Ideguchi, Eiji; Kanungo, Rituparna; et al. (2004). "Experiment on the Synthesis of Element 113 in the Reaction ²⁰⁹Bi(⁷⁰Zn, n)²⁷⁸113". Journal of the Physical Society of Japan. 73 (10): 2593–2596. Bibcode:2004JPSJ...73.2593M. doi:10.1143/JPSJ.73.2593.
11. Barber, Robert C.; Karol, Paul J; Nakahara, Hiromichi; Vardaci, Emanuele; Vogt, Erich W. (2011). "Discovery of the elements with atomic numbers greater than or equal to 113 (IUPAC Technical Report)". Pure and Applied Chemistry. 83 (7): 1485. doi:10.1351/PAC-REP-10-05-01.
12. K. Morita; Morimoto, Kouji; Kaji, Daiya; Haba, Hiromitsu; Ozeki, Kazutaka; Kudou, Yuki; Sumita, Takayuki; Wakabayashi, Yasuo; Yoneda, Akira; Tanaka, Kengo; et al. (2012). "New Results in the Production and Decay of an Isotope, ²⁷⁸113, of the 113th Element". Journal of the Physical Society of Japan. 81 (10): 103201. arXiv:1209.6431. Bibcode:2012JPSJ...81j3201M. doi:10.1143/JPSJ.81.103201. S2CID 119217928.
13. Oganessian, Yu. Ts.; Utyonkov, V.; Lobanov, Yu.; Abdullin, F.; Polyakov, A.; Sagaidak, R.; Shirokovsky, I.; Tsyganov, Yu.; Voinov, A.; Gulbekian, Gulbekian; et al. (2007). "Synthesis of the isotope ²⁸²113 in the ²³⁷Np+⁴⁸Ca fusion reaction" (PDF). Physical Review C. 76 (1): 011601(R). Bibcode:2007PhRvC..76a1601O. doi:10.1103/PhysRevC.76.011601.
14. Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Münzenberg, G.; Antalic, S.; Barth, W.; Burkhard, H. G.; Dahl, L.; Eberhardt, K.; Grzywacz, R.; Hamilton, J. H.; Henderson, R. A.; Kenneally, J. M.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Miernik, K.; Miller, D.; Moody, K. J.; Morita, K.; Nishio, K.; Popeko, A. G.; Roberto, J. B.; Runke, J.; Rykaczewski, K. P.; Saro, S.; Schneidenberger, C.; Schött, H. J.; Shaughnessy, D. A.; Stoyer, M. A.; Thörle-Pospiech, P.; Tinschert, K.; Trautmann, N.; Uusitalo, J.; Yeremin, A. V. (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.
15. Oganessian, Yu. Ts.; Abdullin, F. Sh.; Bailey, P. D.; Benker, D. E.; Bennett, M. E.; Dmitriev, S. N.; Ezold, J. G.; Hamilton, J. H.; et al. (2010). "Synthesis of a New Element with Atomic Number Z=117". Physical Review Letters. 104 (14): 142502. Bibcode:2010PhRvL.104n2502O. doi:10.1103/PhysRevLett.104.142502. PMID 20481935.
16. Oganessian, Yu. Ts.; Penionzhkevich, Yu. E.; Cherepanov, E. A. (2007). "Heaviest Nuclei Produced in ⁴⁸Ca-induced Reactions (Synthesis and Decay Properties)". AIP Conference Proceedings. Vol. 912. pp. 235–246. doi:10.1063/1.2746600.
17. Sonzogni, Alejandro. . National Nuclear Data Center: Brookhaven National Laboratory. Archived from the original on 2007-08-07. Retrieved 2008-06-06.
18. 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.
19. Feng, Z.; Jin, G.; Li, J. (2009). "Production of new superheavy Z=108-114 nuclei with ²³⁸U, ²⁴⁴Pu and ^248,250Cm targets". Physical Review C. 80 (5): 057601. arXiv:0912.4069. doi:10.1103/PhysRevC.80.057601. S2CID 118733755.
20. 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.

• Isotope masses from:
  • M. Wang; G. Audi; A. H. Wapstra; F. G. Kondev; M. MacCormick; X. Xu; et al. (2012). "The AME2012 atomic mass evaluation (II). Tables, graphs and references" (PDF). Chinese Physics C. 36 (12): 1603–2014. Bibcode:2012ChPhC..36....3M. doi:10.1088/1674-1137/36/12/003. S2CID 250839471.
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
• Isotopic compositions and standard atomic masses from:
  • de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
  • Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
• "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
• Half-life, spin, and isomer data selected from the following sources.
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
  • National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
  • Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.