Isotopes of nihonium

Main isotopes of nihonium
Iso­tope Decay
abun­dance half-life (t1/2) mode pro­duct
290Nh[1] syn 2 s? α 286Rg
286Nh syn 8 s α 282Rg
285Nh syn 4 s α 281Rg
284Nh syn 1 s α 280Rg
EC 284Cn
283Nh syn 0.1 s α 279Rg
282Nh syn 70 ms α 278Rg
278Nh syn 1.4 ms α 274Rg

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 290Nh. The longest-lived isotope is 286Nh with a half-life of 19.6 seconds.

List of isotopes

nuclide
symbol		 Z(p) N(n)  
isotopic mass (u)
 		 half-life decay
mode(s)		 daughter
isotope(s)		 nuclear
spin
278Nh 113 165 278.17058(20)# 340 µs α 274Rg
282Nh 113 169 282.17567(39)# 73 ms α 278Rg
283Nh[n 1] 113 170 283.17657(52)# 100(+490−45) ms α 279Rg
284Nh[n 2] 113 171 284.17873(62)# 0.48(+58−17) s α (96.8%) 280Rg  
EC (3.2%)[2][n 3] 284Cn
285Nh[n 4] 113 172 285.17973(89)# 5.5 s[3] α 281Rg
286Nh[n 5] 113 173 286.18221(72)# 19.6 s[3] α 282Rg
290Nh[n 6] 113 177 2 s? α 286Rg
  1. ↑ Not directly synthesized, occurs as decay product of 287Mc
  2. ↑ Not directly synthesized, occurs as decay product of 288Mc
  3. ↑ Heaviest nuclide known to undergo electron capture
  4. ↑ Not directly synthesized, occurs in decay chain of 293Ts
  5. ↑ Not directly synthesized, occurs in decay chain of 294Ts
  6. ↑ Not directly synthesized, occurs in decay chain of 290Fl and 294Lv; unconfirmed

Notes

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.[4]

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.[5] 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.[4] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).[6]

Cold fusion

Before the successful 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.[7] They repeated the experiment in 2003 again without success.[7] 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.[8] They repeated the reaction in several runs in 2005 and were able to synthesize a second atom.[9]

Hot fusion

In June 2006, the Dubna-Livermore team synthesised nihonium directly by bombarding a neptunium-237 target with accelerated calcium-48 nuclei:

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

Two atoms of 282Nh were detected.[10]

As decay product

List of nihonium isotopes observed by decay
Evaporation residue Observed nihonium isotope
294Lv, 290Fl ?290Nh ?
294Ts, 290Mc286Nh[3]
293Ts, 289Mc285Nh[3]
288Mc284Nh[11]
287Mc283Nh[11]

Nihonium has been observed as a decay product of flerovium (via electron capture) and moscovium (via alpha decay). Moscovium currently has four known isotopes; all of them undergo alpha decays to become nihonium nuclei, with mass numbers between 283 and 286. Parent flerovium and moscovium nuclei can be themselves decay products of livermorium and tennessine respectively. To date, no other elements have been known to decay to nihonium.[12] 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:[3]

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 70Zn279Nh1n (278Nh)30 fbDNS[13]
237Np 48Ca285Nh3n (282Nh)0.4 pbDNS[14]

References

  1. ↑ 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.; Scheidenberger, C.; Schött, H. J.; Shaughnessy, D. A.; Stoyer, M. A.; Thörle-Popiesch, P.; Tinschert, K.; Trautmann, N.; Uusitalo, J.; Yeremin, A. V. (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.
  2. ↑ http://xxx.lanl.gov/pdf/1502.03030.pdf
  3. 1 2 3 4 5 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. PMID 20481935. doi:10.1103/PhysRevLett.104.142502.
  4. 1 2 Armbruster, Peter & Münzenberg, Gottfried (1989). "Creating superheavy elements". Scientific American. 34: 36–42.
  5. ↑ 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.
  6. ↑ Fleischmann, Martin; Pons, Stanley (1989). "Electrochemically induced nuclear fusion of deuterium". Journal of Electroanalytical Chemistry and Interfacial Electrochemistry. Elsevier. 261 (2): 301–308. doi:10.1016/0022-0728(89)80006-3. Retrieved 15 October 2012.
  7. 1 2 "Search for element 113", Hofmann et al., GSI report 2003. Retrieved on 3 March 2008
  8. ↑ 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.
  9. ↑ 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.
  10. ↑ 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: 011601(R). Bibcode:2007PhRvC..76a1601O. doi:10.1103/PhysRevC.76.011601.
  11. 1 2 Oganessian, Yu. Ts.; Penionzhkevich, Yu. E.; Cherepanov, E. A. (2007). "AIP Conference Proceedings". 912: 235. doi:10.1063/1.2746600. |chapter= ignored (help)
  12. ↑ Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Retrieved 2008-06-06.
  13. ↑ 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. Bibcode:2007PhRvC..76d4606F. arXiv:0707.2588 Freely accessible. doi:10.1103/PhysRevC.76.044606.
  14. ↑ Feng, Z; Jin, G; Li, J; Scheid, W (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A. 816: 33–51. Bibcode:2009NuPhA.816...33F. arXiv:0803.1117 Freely accessible. doi:10.1016/j.nuclphysa.2008.11.003.
Isotopes of copernicium Isotopes of nihonium Isotopes of flerovium
Table of nuclides
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