Isotopes of meitnerium

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Isotopes of meitnerium  (109Mt)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
274Mt synth 0.64 s α 270Bh
276Mtsynth0.62 sα 272Bh
278Mtsynth4 sα 274Bh
282Mtsynth67 s? [2] α 278Bh

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.

Contents

List of isotopes

Nuclide
[n 1]
Z N Isotopic mass (Da)
[n 2] [n 3]
Half-life [1]
Decay
mode
[1]
Daughter
isotope

Spin and
parity [1]
[n 4] [n 5]
Excitation energy
266Mt109157266.137060(100)2.0(5) ms α 262Bh
268Mt [n 6] 109159268.13865(25)#23(7) msα264Bh5+#, 6+#
268mMt [n 7] 0+X keV70+100
−30
 ms
α264Bh
270Mt [n 8] 109161270.14033(18)#800(400) msα266Bh
270mMt [n 7] 1.1 s?α266Bh
274Mt [n 9] 109165274.14725(38)# [3] 640+760
−230
 ms
[3]
α270Bh
275Mt [n 10] 109166275.14882(50)#20+13
−6
 ms
[3]
α271Bh
276Mt [n 11] 109167276.15159(59)#620+60
−40
 ms
[3]
α272Bh
277Mt [n 12] 109168277.15327(82)#5+9
−2
 ms
[4]
SF (various)
278Mt [n 13] 109169278.15631(68)#6(3) sα274Bh
282Mt [n 14] 10917367 s?α278Bh
This table header & footer:
  1. mMt  Excited nuclear isomer.
  2. ()  Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. #  Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. () spin value  Indicates spin with weak assignment arguments.
  5. #  Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. Not directly synthesized, occurs as decay product of 272Rg
  7. 1 2 This isomer is unconfirmed
  8. Not directly synthesized, occurs in decay chain of 278Nh
  9. Not directly synthesized, occurs in decay chain of 282Nh
  10. Not directly synthesized, occurs in decay chain of 287Mc
  11. Not directly synthesized, occurs in decay chain of 288Mc
  12. Not directly synthesized, occurs in decay chain of 293Ts
  13. Not directly synthesized, occurs in decay chain of 294Ts
  14. Not directly synthesized, occurs in decay chain of 290Fl and 294Lv; unconfirmed

Isotopes and nuclear properties

Nucleosynthesis

Super-heavy elements such as meitnerium are produced by bombarding lighter elements in particle accelerators that induce fusion reactions. Whereas the lightest isotope of meitnerium, meitnerium-266, can be synthesized directly this way, all the heavier meitnerium isotopes have only been observed as decay products of elements with higher atomic numbers. [5]

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. [6] 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. [5] Nevertheless, the products of hot fusion tend to still have more neutrons overall. The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion). [7]

The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z = 109.

TargetProjectileCNAttempt result
208Pb59Co267MtSuccessful reaction
209Bi58Fe267MtSuccessful reaction
227Ac48Ca275MtReaction yet to be attempted
238U37Cl275MtFailure to date
244Pu31P275MtReaction yet to be attempted
248Cm27Al275MtReaction yet to be attempted
250Cm27Al277MtReaction yet to be attempted
249Bk26Mg275MtReaction yet to be attempted
254Es22Ne276MtFailure to date

Cold fusion

After the first successful synthesis of meitnerium in 1982 by the GSI team, [8] a team at the Joint Institute for Nuclear Research in Dubna, Russia, also tried to observe the new element by bombarding bismuth-209 with iron-58. In 1985 they managed to identity alpha decays from the descendant isotope 246 Cf indicating the formation of meitnerium. The observation of a further two atoms of 266Mt from the same reaction was reported in 1988 and of another 12 in 1997 by the German team at GSI. [9] [10]

The same meitnerium isotope was also observed by the Russian team at Dubna in 1985 from the reaction:

208
82
Pb
+ 59
27
Co
266
109
Mt
+
n

by detecting the alpha decay of the descendant 246Cf nuclei. In 2007, an American team at the Lawrence Berkeley National Laboratory (LBNL) confirmed the decay chain of the 266Mt isotope from this reaction. [11]

Hot fusion

In 2002–2003, the team at LBNL attempted to generate the isotope 271Mt to study its chemical properties by bombarding uranium-238 with chlorine-37, but without success. [12] Another possible reaction that would form this isotope would be the fusion of berkelium-249 with magnesium-26; however, the yield for this reaction is expected to be very low due to the high radioactivity of the berkelium-249 target. [13] Other potentially longer-lived isotopes were unsuccessfully targeted by a team at Lawrence Livermore National Laboratory (LLNL) in 1988 by bombarding einsteinium-254 with neon-22. [12]

Decay products

List of meitnerium isotopes observed by decay
Evaporation residueObserved meitnerium isotope
294Lv, 290Fl, 290Nh, 286Rg ?282Mt ?
294Ts, 290Mc, 286Nh, 282Rg278Mt [14]
293Ts, 289Mc, 285Nh, 281Rg277Mt [4]
288Mc, 284Nh, 280Rg276Mt [15]
287Mc, 283Nh, 279Rg275Mt [15]
286Mc, 282Nh, 278Rg274Mt [15]
278Nh, 274Rg270Mt [16]
272Rg268Mt [17]

All the isotopes of meitnerium except meitnerium-266 have been detected only in the decay chains of elements with a higher atomic number, such as roentgenium. Roentgenium currently has eight known isotopes; all but one of them undergo alpha decays to become meitnerium nuclei, with mass numbers between 268 and 282. Parent roentgenium nuclei can be themselves decay products of nihonium, flerovium, moscovium, livermorium, or tennessine. [18] For example, in January 2010, the Dubna team (JINR) identified meitnerium-278 as a product in the decay of tennessine via an alpha decay sequence: [14]

294
117
Ts
290
115
Mc
+ 4
2
He
290
115
Mc
286
113
Nh
+ 4
2
He
286
113
Nh
282
111
Rg
+ 4
2
He
282
111
Rg
278
109
Mt
+ 4
2
He

Nuclear isomerism

270Mt

Two atoms of 270Mt have been identified in the decay chains of 278Nh. The two decays have very different lifetimes and decay energies and are also produced from two apparently different isomers of 274Rg. The first isomer decays by emission of an alpha particle with energy 10.03 MeV and has a lifetime of 7.16 ms. The other alpha decays with a lifetime of 1.63 s; the decay energy was not measured. An assignment to specific levels is not possible with the limited data available and further research is required. [16]

268Mt

The alpha decay spectrum for 268Mt appears to be complicated from the results of several experiments. Alpha particles of energies 10.28, 10.22 and 10.10 MeV have been observed, emitted from 268Mt atoms with half-lives of 42 ms, 21 ms and 102 ms respectively. The long-lived decay must be assigned to an isomeric level. The discrepancy between the other two half-lives has yet to be resolved. An assignment to specific levels is not possible with the data available and further research is required. [17]

Chemical yields of isotopes

Cold fusion

The table below provides cross-sections and excitation energies for cold fusion reactions producing meitnerium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel.

ProjectileTargetCN1n2n3n
58Fe209Bi267Mt7.5 pb
59Co208Pb267Mt2.6 pb, 14.9 MeV

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; HIVAP = heavy-ion vaporisation statistical-evaporation model; σ = cross section

TargetProjectileCNChannel (product)σmaxModelRef
238U37Cl275Mt3n (272Mt)13.31 pbDNS [19]
244Pu31P275Mt3n (272Mt)4.25 pbDNS [19]
243Am30Si273Mt3n (270Mt)22 pbHIVAP [20]
243Am28Si271Mt4n (267Mt)3 pbHIVAP [20]
248Cm27Al275Mt3n (272Mt)27.83 pbDNS [19]
250Cm27Al277Mt5n (272Mt)97.44 pbDNS [19]
249Bk26Mg275Mt4n (271Mt)9.5 pbHIVAP [20]
254Es22Ne276Mt4n (272Mt)8 pbHIVAP [20]
254Es20Ne274Mt4-5n (270,269Mt)3 pbHIVAP [20]

Related Research Articles

<span class="mw-page-title-main">Bohrium</span> Chemical element, symbol Bh and atomic number 107

Bohrium is a synthetic chemical element; it has symbol Bh and atomic number 107. It is named after Danish physicist Niels Bohr. As a synthetic element, it can be created in particle accelerators but is not found in nature. All known isotopes of bohrium are highly radioactive; the most stable known isotope is 270Bh with a half-life of approximately 2.4 minutes, though the unconfirmed 278Bh may have a longer half-life of about 11.5 minutes.

<span class="mw-page-title-main">Meitnerium</span> Chemical element, symbol Mt and atomic number 109

Meitnerium is a synthetic chemical element; it has symbol Mt and atomic number 109. It is an extremely radioactive synthetic element. The most stable known isotope, meitnerium-278, has a half-life of 4.5 seconds, although the unconfirmed meitnerium-282 may have a longer half-life of 67 seconds. The GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany, first created this element in 1982. It is named after Lise Meitner.

<span class="mw-page-title-main">Rutherfordium</span> Chemical element, symbol Rf and atomic number 104

Rutherfordium is a synthetic chemical element; it has symbol Rf and atomic number 104. It is named after physicist Ernest Rutherford. As a synthetic element, it is not found in nature and can only be made in a particle accelerator. It is radioactive; the most stable known isotope, 267Rf, has a half-life of about 48 minutes.

<span class="mw-page-title-main">Roentgenium</span> Chemical element, symbol Rg and atomic number 111

Roentgenium is a synthetic chemical element; it has symbol Rg and atomic number 111. It is extremely radioactive and can only be created in a laboratory. The most stable known isotope, roentgenium-282, has a half-life of 120 seconds, although the unconfirmed roentgenium-286 may have a longer half-life of about 10.7 minutes. Roentgenium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It is named after the physicist Wilhelm Röntgen, who discovered X-rays. Only a few roentgenium atoms have ever been synthesized, and they have no practical application.

Livermorium is a synthetic chemical element; it has symbol Lv and atomic number 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. Five isotopes of livermorium are known, with mass numbers of 288 and 290–293 inclusive; the longest-lived among them is livermorium-293 with a half-life of about 60 milliseconds. A sixth possible isotope with mass number 294 has been reported but not yet confirmed.

Moscovium is a synthetic chemical element; it has symbol Mc and atomic number 115. It was first synthesized in 2003 by a joint team of Russian and American scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. In December 2015, it was recognized as one of four new elements by the Joint Working Party of international scientific bodies IUPAC and IUPAP. On 28 November 2016, it was officially named after the Moscow Oblast, in which the JINR is situated.

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

Nihonium is a synthetic chemical element; it has 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.

Rutherfordium (104Rf) is a synthetic element and thus has no stable isotopes. A standard atomic weight cannot be given. The first isotope to be synthesized was either 259Rf in 1966 or 257Rf in 1969. There are 16 known radioisotopes from 253Rf to 270Rf and several isomers. The longest-lived isotope is 267Rf with a half-life of 48 minutes, and the longest-lived isomer is 263mRf with a half-life of 8 seconds.

Dubnium (105Db) is a synthetic element, thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 261Db in 1968. Thirteen radioisotopes are known, ranging from 255Db to 270Db, along with one isomer (257mDb); two more isomers have been reported but are unconfirmed. The longest-lived known isotope is 268Db with a half-life of 16 hours.

Seaborgium (106Sg) is a synthetic element and so has no stable isotopes. A standard atomic weight cannot be given. The first isotope to be synthesized was 263Sg in 1974. There are 13 known radioisotopes from 258Sg to 271Sg and 4 known isomers. The longest-lived isotope is 269Sg with a half-life of 14 minutes.

Bohrium (107Bh) is an artificial element. Like all artificial elements, it has no stable isotopes, and a standard atomic weight cannot be given. The first isotope to be synthesized was 262Bh in 1981. There are 11 known isotopes ranging from 260Bh to 274Bh, and 1 isomer, 262mBh. The longest-lived isotope is 270Bh with a half-life of 2.4 minutes, although the unconfirmed 278Bh may have an even longer half-life of about 690 seconds.

Hassium (108Hs) 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 265Hs in 1984. There are 13 known isotopes from 263Hs to 277Hs and 1–4 isomers. The most stable isotope of hassium cannot be determined based on existing data due to uncertainty that arises from the low number of measurements. The half-lives of 269Hs and 271Hs are about 12 seconds, whereas that of 270Hs is about 7.6 seconds. It is also possible that 277mHs is more stable than these, with its half-life likely being 130±100 seconds, but only one event of decay of this isotope has been registered as of 2016.

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 six known isotopes, along with the unconfirmed 290Fl, and possibly two nuclear isomers. The longest-lived isotope is 289Fl with a half-life of 1.9 seconds, but 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 five known radioisotopes, with mass numbers 288 and 290–293, as well as a few suggestive indications of a possible heavier isotope 294Lv. The longest-lived known isotope is 293Lv with a half-life of 70 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.

References

  1. 1 2 3 4 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.; 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.
  3. 1 2 3 4 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.
  4. 1 2 Oganessian, Yu. Ts.; et al. (2013). "Experimental studies of the 249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope 277Mt". Physical Review C . 87 (5): 054621. Bibcode:2013PhRvC..87e4621O. doi: 10.1103/PhysRevC.87.054621 .
  5. 1 2 Armbruster, Peter & Munzenberg, Gottfried (1989). "Creating superheavy elements". Scientific American. 34: 36–42.
  6. 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 .
  7. 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.
  8. Münzenberg, G.; et al. (1982). "Observation of one correlated α-decay in the reaction 58Fe on 209Bi→267109". Zeitschrift für Physik A . 309 (1): 89–90. Bibcode:1982ZPhyA.309...89M. doi:10.1007/BF01420157. S2CID   120062541.
  9. Münzenberg, G.; Hofmann, S.; Heßberger, F. P.; et al. (1988). "New results on element 109". Zeitschrift für Physik A. 330 (4): 435–436. Bibcode:1988ZPhyA.330..435M. doi:10.1007/BF01290131. S2CID   121364541.
  10. Hofmann, S.; Heßberger, F. P.; Ninov, V.; et al. (1997). "Excitation function for the production of 265108 and 266109". Zeitschrift für Physik A. 358 (4): 377–378. Bibcode:1997ZPhyA.358..377H. doi:10.1007/s002180050343. S2CID   124304673.
  11. Nelson, S. L.; Gregorich, K. E.; Dragojević, I.; et al. (2009). "Comparison of complementary reactions in the production of Mt". Physical Review C. 79 (2): 027605. Bibcode:2009PhRvC..79b7605N. doi:10.1103/PhysRevC.79.027605. S2CID   73657127.
  12. 1 2 Zielinski P. M. et al. (2003). "The search for 271Mt via the reaction 238U + 37Cl" Archived 2012-02-06 at the Wayback Machine , GSI Annual report. Retrieved on 2008-03-01
  13. Haire, Richard G. (2006). "Transactinides and the future elements". In Morss; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN   1-4020-3555-1.
  14. 1 2 Oganessian, Yu. Ts.; 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.
  15. 1 2 3 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.
  16. 1 2 Morita, Kosuke; Morimoto, Kouji; Kaji, Daiya; Akiyama, Takahiro; Goto, Sin-ichi; Haba, Hiromitsu; Ideguchi, Eiji; Kanungo, Rituparna; Katori, Kenji; Koura, Hiroyuki; Kudo, Hisaaki; Ohnishi, Tetsuya; Ozawa, Akira; Suda, Toshimi; Sueki, Keisuke; Xu, HuShan; Yamaguchi, Takayuki; Yoneda, Akira; Yoshida, Atsushi; Zhao, YuLiang (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 .
  17. 1 2 Hofmann, S.; Ninov, V.; Heßberger, F. P.; Armbruster, P.; Folger, H.; Münzenberg, G.; Schött, H. J.; Popeko, A. G.; Yeremin, A. V.; Andreyev, A. N.; Saro, S.; Janik, R.; Leino, M. (1995). "The new element 111" (PDF). Zeitschrift für Physik A. 350 (4): 281–282. Bibcode:1995ZPhyA.350..281H. doi:10.1007/BF01291182. S2CID   18804192. Archived from the original (PDF) on 2014-01-16.
  18. Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Archived from the original on 2018-03-07. Retrieved 2008-06-06.
  19. 1 2 3 4 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: 057601. arXiv: 0912.4069 . doi:10.1103/PhysRevC.80.057601. S2CID   118733755.
  20. 1 2 3 4 5 Wang, K.; et al. (2004). "A Proposed Reaction Channel for the Synthesis of the Superheavy Nucleus Z = 109". Chinese Physics Letters . 21 (3): 464–467. arXiv: nucl-th/0402065 . Bibcode:2004ChPhL..21..464W. doi:10.1088/0256-307X/21/3/013. S2CID   117308338.