Isotopes of ununtrium

Ununtrium (Uut, element 113) is a synthetic element with atomic number 113. Being synthetic, a standard atomic mass cannot be given and like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was ²⁸⁴Uut as a decay product of ²⁸⁸Uup in 2003. The first isotope to be directly synthesized was ²⁷⁸Uut in 2004. There are 6 known radioisotopes from ²⁷⁸Uut to ²⁸⁶Uut. The longest-lived isotope is ²⁸⁶Uut with a half-life of 19.6 seconds.

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)	daughter isotope(s)	nuclear spin
^278Uut	113	165	278.17058(20)#	340 µs	α	^274Rg
^282Uut	113	169	282.17567(39)#	73 ms	α	^278Rg
^283Uut[n 1]	113	170	283.17657(52)#	100(+490−45) ms	α	^279Rg
^284Uut[n 2]	113	171	284.17873(62)#	0.48(+58−17) s	α	^280Rg
^285Uut[n 3]	113	172	285.17973(89)#	5.5 s[1]	α	^281Rg
^286Uut[n 4]	113	173	286.18221(72)#	19.6 s[1]	α	^282Rg

1. Not directly synthesized, occurs as decay product of ²⁸⁷Uup
2. Not directly synthesized, occurs as decay product of ²⁸⁸Uup
3. Not directly synthesized, occurs in decay chain of ²⁹³Uus
4. Not directly synthesized, occurs in decay chain of ²⁹⁴Uus

Notes

• Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
• Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.

Isotopes and nuclear properties

Nucleosynthesis

Super-heavy elements such as ununtrium are produced by bombarding lighter elements in particle accelerators that induce fusion reactions. Whereas most of the isotopes of ununtrium can be synthesized directly this way, some heavier ones have only been observed as decay products of elements with higher atomic numbers.^[2]

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.^[3] 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.^[2] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).^[4]

Cold fusion

Before the successful synthesis of ununtrium by the RIKEN team, scientists at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung) in Darmstadt, Germany also tried to synthesize ununtrium by bombarding bismuth-209 with zinc-70 in 1998. No ununtrium atoms were identified in two separate runs of the reaction.^[5] They repeated the experiment in 2003 again without success.^[5] 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 ²⁷⁸Uut.^[6] They repeated the reaction in several runs in 2005 and were able to synthesize a second atom.^[7]

Hot fusion

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

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

Two atoms of ²⁸²Uut were detected.^[8]

As decay product

List of ununtrium isotopes observed by decay

Evaporation residue	Observed ununtrium isotope
^294Uus, ^290Uup	^286Uut[1]
^293Uus, ^289Uup	^285Uut[1]
^288Uup	^284Uut[9]
^287Uup	^283Uut[9]

Ununtrium has been observed as decay products of ununpentium. Ununpentium currently has four known isotopes; all of them undergo alpha decays to become ununtrium nuclei, with mass numbers between 283 and 286. Parent ununpentium nuclei can be themselves decay products of ununseptium. To date, no other elements have been known to decay to ununtrium.^[10] For example, in January 2010, the Dubna team (JINR) identified ununtrium-286 as a product in the decay of ununseptium via an alpha decay sequence:^[1]

294
117Uus → 290
115Uup + 4
2He

290
115Uup → 286
113Uut + 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	^279Uut	1n (^278Uut)	30 fb	DNS	[11]
^237Np	^48Ca	^285Uut	3n (^282Uut)	0.4 pb	DNS	[12]

References

1. 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.
2. Armbruster, Peter & Münzenberg, Gottfried (1989). "Creating superheavy elements". Scientific American 34: 36–42.
3. 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.
4. 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.
5. "Search for element 113", Hofmann et al., GSI report 2003. Retrieved on 3 March 2008
6. 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.
7. 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.
8. 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.
9. Oganessian, Yu. Ts.; Penionzhkevich, Yu. E.; Cherepanov, E. A. (2007). "AIP Conference Proceedings" 912: 235. doi:10.1063/1.2746600. |chapter= ignored (help)
10. Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Retrieved 2008-06-06.
11. 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.
12. 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. arXiv:0803.1117. Bibcode:2009NuPhA.816...33F. doi:10.1016/j.nuclphysa.2008.11.003.

• 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.
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). 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:
  • J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683.
  • M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
• Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
  • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
  • N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.