Isotopes of bohrium

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Isotopes of bohrium  (107Bh)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
267Bh synth 17 s α 263Db
270Bhsynth2.4 minα 266Db
271Bhsynth2.9 s [2] α 267Db
272Bhsynth8.8 sα 268Db
274Bhsynth40 s [3] α 270Db
278Bhsynth11.5 min? [4] SF –

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.

Contents

List of isotopes

Nuclide
[n 1] 		Z N Isotopic mass (Da)
[n 2] [n 3] 		Half-life
Decay
mode
[n 4] 		Daughter
isotope
Spin and
parity
[n 5]
Excitation energy
260Bh [5] 107153260.12166(26)#41(14) ms
[35+19
−9 ms]		 α 256Db
261Bh [6] 107154261.121400(190) [7] 12.8(3.2) ms
[11.8+3.9
−2.4 ms]		α257Db(5/2−)
SF (rare)(various)
262Bh [8] 107155262.122650(100) [9] 135+15
−12 ms		α (>94.9%)258Db
β+ (<3.0%)262Sg
SF (2.1%)(various)
262mBh220(50) keV13.2+1.2
−1.0 ms		α258Db
264Bh107157264.12459(19)#1.07(21) sα (85%)260Db
SF(β+?) (15%) [10] (various)
265Bh [11] 107158265.12491(25)#1.19(52) s
[0.94+0.70
−0.31 s]		α261Db
266Bh107159266.12679(18)#10.0+2.6
−1.7 s [12] 		α262Db
β+?266Sg
267Bh107160267.12750(28)#22(10) s
[17+14
−6 s]		α263Db
270Bh [n 6] 107163270.13336(31)#2.4+4.4
−0.9 min [13] 		α266Db
271Bh [n 7] 107164271.13526(48)#2.9+2.2
−0.9 s [13] 		α267Db
272Bh [n 8] 107165272.13826(58)#8.8(7) s [13] α268Db
274Bh [n 9] 107167274.14355(65)#57(27) s
[44+34
−13 s] [14] 		α270Db
278Bh [n 10] 10717111.5 min?SF(various)
This table header & footer:
  1. ↑ mBh – 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. ↑ Modes of decay:
    SF: Spontaneous fission
  5. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  6. ↑ Not directly synthesized, occurs in decay chain of 282Nh
  7. ↑ Not directly synthesized, occurs in decay chain of 287Mc
  8. ↑ Not directly synthesized, occurs in decay chain of 288Mc
  9. ↑ Not directly synthesized, occurs in decay chain of 294Ts
  10. ↑ Not directly synthesized, occurs in decay chain of 290Fl and 294Lv; unconfirmed

Nucleosynthesis

Superheavy elements such as bohrium are produced by bombarding lighter elements in particle accelerators that induce fusion reactions. Whereas most of the isotopes of bohrium can be synthesized directly this way, some heavier ones have only been observed as decay products of elements with higher atomic numbers. [15]

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. [16] 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. As the fused nuclei cool to the ground state, they require emission of only one or two neutrons, thus allowing for the generation of more neutron-rich products. [15] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion). [17]

The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z = 107.

TargetProjectileCNAttempt result
208Pb55Mn263BhSuccessful reaction
209Bi54Cr263BhSuccessful reaction
209Bi52Cr261BhSuccessful reaction
238U31P269BhSuccessful reaction
243Am26Mg269BhSuccessful reaction
248Cm23Na271BhSuccessful reaction
249Bk22Ne271BhSuccessful reaction

Cold fusion

Before the first successful synthesis of hassium in 1981 by the GSI team, the synthesis of bohrium was first attempted in 1976 by scientists at the Joint Institute for Nuclear Research at Dubna using this cold fusion reaction. They detected two spontaneous fission activities, one with a half-life of 1–2 ms and one with a half-life of 5 s. Based on the results of other cold fusion reactions, they concluded that they were due to 261Bh and 257Db respectively. However, later evidence gave a much lower SF branching for 261Bh reducing confidence in this assignment. The assignment of the dubnium activity was later changed to 258Db, presuming that the decay of bohrium was missed. The 2 ms SF activity was assigned to 258Rf resulting from the 33% EC branch. The GSI team studied the reaction in 1981 in their discovery experiments. Five atoms of 262Bh were detected using the method of correlation of genetic parent-daughter decays. [18] In 1987, an internal report from Dubna indicated that the team had been able to detect the spontaneous fission of 261Bh directly. The GSI team further studied the reaction in 1989 and discovered the new isotope 261Bh during the measurement of the 1n and 2n excitation functions but were unable to detect an SF branching for 261Bh. [19] They continued their study in 2003 using newly developed bismuth(III) fluoride (BiF3) targets, used to provide further data on the decay data for 262Bh and the daughter 258Db. The 1n excitation function was remeasured in 2005 by the team at the Lawrence Berkeley National Laboratory (LBNL) after some doubt about the accuracy of previous data. They observed 18 atoms of 262Bh and 3 atoms of 261Bh and confirmed the two isomers of 262Bh. [20]

In 2007, the team at LBNL studied the analogous reaction with chromium-52 projectiles for the first time to search for the lightest bohrium isotope 260Bh:

209
83Bi
 + 52
24Cr
 → 260
107Bh
 +
n

The team successfully detected 8 atoms of 260Bh decaying by alpha decay to 256Db, emitting alpha particles with energy 10.16  MeV. The alpha decay energy indicates the continued stabilizing effect of the N=152 closed shell. [21]

The team at Dubna also studied the reaction between lead-208 targets and manganese-55 projectiles in 1976 as part of their newly established cold fusion approach to new elements:

208
82Pb
 + 55
25Mn
 → 262
107Bh
 +
n

They observed the same spontaneous fission activities as those observed in the reaction between bismuth-209 and chromium-54 and again assigned them to 261Bh and 257Db. Later evidence indicated that these should be reassigned to 258Db and 258Rf (see above). In 1983, they repeated the experiment using a new technique: measurement of alpha decay from a decay product that had been separated out chemically. The team were able to detect the alpha decay from a decay product of 262Bh, providing some evidence for the formation of bohrium nuclei. This reaction was later studied in detail using modern techniques by the team at LBNL. In 2005 they measured 33 decays of 262Bh and 2 atoms of 261Bh, providing an excitation function for the reaction emitting one neutron and some spectroscopic data of both 262Bh isomers. The excitation function for the reaction emitting two neutrons was further studied in a 2006 repeat of the reaction. The team found that the reaction emitting one neutron had a higher cross section than the corresponding reaction with a 209Bi target, contrary to expectations. Further research is required to understand the reasons. [22] [23]

Hot fusion

The reaction between uranium-238 targets and phosphorus-31 projectiles was first studied in 2006 at the LBNL as part of their systematic study of fusion reactions using uranium-238 targets:

238
92U
 + 31
15P
 → 264
107Bh
 + 5
n

Results have not been published but preliminary results appear to indicate the observation of spontaneous fission, possibly from 264Bh. [24]

Recently, the team at the Institute of Modern Physics (IMP), Lanzhou, have studied the nuclear reaction between americium-243 targets and accelerated nuclei of magnesium-26 in order to synthesise the new isotope 265Bh and gather more data on 266Bh:

243
95Am
 + 26
12Mg
 → 269−x
107Bh
 + x
n
 (x = 3, 4, or 5)

In two series of experiments, the team measured partial excitation functions for the reactions emitting three, four, and five neutrons. [25]

The reaction between targets of curium-248 and accelerated nuclei of sodium-23 was studied for the first time in 2008 by the team at RIKEN, Japan, in order to study the decay properties of 266Bh, which is a decay product in their claimed decay chains of nihonium: [26]

248
96Cm
 + 23
11Na
 → 271−x
107Bh
 + x
n
 (x = 4 or 5)

The decay of 266Bh by the emission of alpha particles with energies of 9.05–9.23 MeV was further confirmed in 2010. [27]

The first attempts to synthesize bohrium by hot fusion pathways were performed in 1979 by the team at Dubna, using the reaction between accelerated nuclei of neon-22 and targets of berkelium-249:

249
97Bk
 + 22
10Ne
 → 271−x
107Bh
 + x
n
 (x = 4 or 5)

The reaction was repeated in 1983. In both cases, they were unable to detect any spontaneous fission from nuclei of bohrium. More recently, hot fusions pathways to bohrium have been re-investigated in order to allow for the synthesis of more long-lived, neutron rich isotopes to allow a first chemical study of bohrium. In 1999, the team at LBNL claimed the discovery of long-lived 267Bh (5 atoms) and 266Bh (1 atom). [28] Later, both of these were confirmed. [29] The team at the Paul Scherrer Institute (PSI) in Bern, Switzerland later synthesized 6 atoms of 267Bh in the first definitive study of the chemistry of bohrium. [30]

As decay products

List of bohrium isotopes observed by decay
Evaporation residueObserved bohrium isotope
294Lv, 290Fl, 290Nh, 286Rg, 282Mt ?278Bh ?
294Ts, 290Mc, 286Nh, 282Rg, 278Mt274Bh [3]
288Mc, 284Nh, 280Rg, 276Mt272Bh [31] [32]
287Mc, 283Nh, 279Rg, 275Mt271Bh [31]
286Mc, 282Nh, 278Rg, 274Mt270Bh [31]
278Nh, 274Rg, 270Mt266Bh [32]
272Rg, 268Mt264Bh [33]
266Mt262Bh [34]

Bohrium has been detected in the decay chains of elements with a higher atomic number, such as meitnerium. Meitnerium currently has seven known isotopes; all of them undergo alpha decays to become bohrium nuclei, with mass numbers between 262 and 274. Parent meitnerium nuclei can be themselves decay products of roentgenium, nihonium, flerovium, moscovium, livermorium, or tennessine. [35] For example, in January 2010, the Dubna team (JINR) identified bohrium-274 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
286
113Nh
 → 282
111Rg
 + 4
2He
282
111Rg
 → 278
109Mt
 + 4
2He
278
109Mt
 → 274
107Bh
 + 4
2He

Nuclear isomerism

262Bh

The only confirmed example of isomerism in bohrium is in the isotope 262Bh. Direct synthesis of 262Bh results in two states, a ground state and an isomeric state. The ground state is confirmed to decay by alpha decay, emitting alpha particles with energies of 10.08, 9.82, and 9.76 MeV, and has a revised half-life of 84 ms. The excited state also decays by alpha decay, emitting alpha particles with energies of 10.37 and 10.24 MeV, and has a revised half-life of 9.6 ms. [18]

Chemical yields of isotopes

Cold fusion

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

ProjectileTargetCN1n2n3n
55Mn208Pb263Bh590 pb, 14.1 MeV~35 pb
54Cr209Bi263Bh510 pb, 15.8 MeV~50 pb
52Cr209Bi261Bh59 pb, 15.0 MeV

Hot fusion

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

ProjectileTargetCN3n4n5n
26Mg243Am271Bh+++
22Ne249Bk271Bh~96 pb+

Related Research Articles

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.

Meitnerium is a synthetic chemical element; it has symbol Mt and atomic number 109. It is named after Lise Meitner and 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.

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.

Darmstadtium is a synthetic chemical element; it has symbol Ds and atomic number 110. It is extremely radioactive: the most stable known isotope, darmstadtium-281, has a half-life of approximately 14 seconds. Darmstadtium was first created in 1994 by the GSI Helmholtz Centre for Heavy Ion Research in the city of Darmstadt, Germany, after which it was named.

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 80 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.

Nobelium (102No) 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 254No in 1966. There are fourteen known radioisotopes, which are 248No to 260No and 262No, and many isomers. The longest-lived isotope is 259No with a half-life of 58 minutes. The longest-lived isomer is 251m1No with a half-life of 1.02 seconds.

Lawrencium (103Lr) 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 258Lr in 1961. There are fourteen known isotopes from 251Lr to 266Lr, and seven isomers. The longest-lived known isotope is 266Lr with a half-life of 11 hours.

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 thirteen known radioisotopes from 258Sg to 271Sg and five known isomers. The longest-lived isotopes are 267Sg with a half-life of 9.8 minutes and 269Sg with a half-life of 5 minutes. Due to a low number of measurements, and the consequent overlapping measurement uncertainties at the confidence level corresponding to one standard deviation, a definite assignment of the most stable isotope cannot be made.

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 up to six isomers. The most stable known isotope is 271Hs, with a half-life of about 46 seconds, though this assignment is not definite due to uncertainty arising from a low number of measurements. The isotopes 269Hs and 270Hs respectively have half-lives of about 12 seconds and 7.6 seconds. It is also possible that the isomer 277mHs is more stable than these, with a reported half-life 130±100 seconds, but only one event of decay of this isotope has been registered as of 2016.

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. However, the unconfirmed 282Ds might have an even longer half-life of 67 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.

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 a synthetic 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 53 ms.

Unbiunium, also known as eka-actinium or element 121, is a hypothetical chemical element; it has 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.

References

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  20. ↑ "Entrance Channel Effects in the Production of 262,261Bh", Nelson et al., LBNL repositories 2005. Retrieved 2008-03-04
  21. ↑ Nelson, S.; Gregorich, K.; Dragojević, I.; Garcia, M.; Gates, J.; Sudowe, R.; Nitsche, H. (2008). "Lightest Isotope of Bh Produced via the Bi209(Cr52,n)Bh260 Reaction". Physical Review Letters. 100 (2): 22501. Bibcode:2008PhRvL.100b2501N. doi:10.1103/PhysRevLett.100.022501. PMID   18232860. S2CID   1242390.
  22. ↑ Folden Iii, C. M.; Nelson; Düllmann; Schwantes; Sudowe; Zielinski; Gregorich; Nitsche; Hoffman (2006). "Excitation function for the production of 262Bh (Z=107) in the odd-Z-projectile reaction 208Pb(55Mn, n)". Physical Review C. 73 (1): 014611. Bibcode:2006PhRvC..73a4611F. doi:10.1103/PhysRevC.73.014611. S2CID   73712859.
  23. ↑ "Excitation function for the production of 262Bh (Z=107) in the odd-Z-projectile reaction 208Pb(55Mn, n)", Folden et al., LBNL repositories, May 19, 2005. Retrieved on 2008-02-29
  24. ↑ Hot fusion studies at the BGS with light projectiles and 238U targets Archived 2011-07-19 at the Wayback Machine , J. M. Gates
  25. ↑ Gan, Z. G.; Guo, J. S.; Wu, X. L.; Qin, Z.; Fan, H. M.; Lei, X.G.; Liu, H.Y.; Guo, B.; et al. (2004). "New isotope 265Bh". The European Physical Journal A. 20 (3): 385–387. Bibcode:2004EPJA...20..385G. doi:10.1140/epja/i2004-10020-2. S2CID   120622108.
  26. ↑ Morita, Kosuke; Morimoto, Kouji; Kaji, Daiya; Haba, Hiromitsu; Ozeki, Kazutaka; Kudou, Yuki; Sato, Nozomi; Sumita, Takayuki; Yoneda, Akira; Ichikawa, Takatoshi; Fujimori, Yasuyuki; Goto, Sin-Ichi; Ideguchi, Eiji; Kasamatsu, Yoshitaka; Katori, Kenji; Komori, Yukiko; Koura, Hiroyuki; Kudo, Hisaaki; Ooe, Kazuhiro; Ozawa, Akira; Tokanai, Fuyuki; Tsukada, Kazuaki; Yamaguchi, Takayuki; Yoshida, Atsushi; et al. (2009). "Decay Properties of 266Bh and 262Db Produced in the 248Cm + 23Na Reaction". Journal of the Physical Society of Japan. 78 (6): 064201. arXiv: 0904.1093 . Bibcode:2009JPSJ...78f4201M. doi:10.1143/JPSJ.78.064201. S2CID   16415500.
  27. ↑ Morita, K.; Morimoto, K.; Kaji, D.; Haba, H.; Ozeki, K.; Kudou, Y.; Sato, N.; Sumita, T.; Yoneda, A.; Ichikawa, T.; Fujimori, Y.; Goto, S.; Ideguchi, E.; Kasamatsu, Y.; Katori, K.; Komori, Y.; Koura, H.; Kudo, H.; Ooe, K.; Ozawa, A.; Tokanai, F.; Tsukada, K.; Yamaguchi, T.; Yoshida, A.; Susa, Hajime; Arnould, Marcel; Gales, Sydney; Motobayashi, Tohru; Scheidenberger, Christoph; Utsunomiya, Hiroaki (2010). "Decay Properties of 266Bh and 262Db Produced in the 248Cm+23Na Reaction—Further Confirmation of the [sup 278]113 Decay Chain—". AIP Conference Proceedings: 331. doi:10.1063/1.3455961.{{cite journal}}: Cite journal requires |journal= (help)
  28. ↑ Wilk, P. A.; Gregorich, KE; Turler, A; Laue, CA; Eichler, R; Ninov V, V; Adams, JL; Kirbach, UW; et al. (2000). "Evidence for New Isotopes of Element 107: 266Bh and 267Bh". Physical Review Letters. 85 (13): 2697–700. Bibcode:2000PhRvL..85.2697W. doi:10.1103/PhysRevLett.85.2697. PMID   10991211.
  29. ↑ Münzenberg, G.; Gupta, M. (2011). "Production and Identification of Transactinide Elements". Handbook of Nuclear Chemistry. pp. 877–923. doi:10.1007/978-1-4419-0720-2_19. ISBN   978-1-4419-0719-6.
  30. ↑ "Gas chemical investigation of bohrium (Bh, element 107)" Archived 2008-02-28 at the Wayback Machine , Eichler et al., GSI Annual Report 2000. Retrieved on 2008-02-29
  31. 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.
  32. 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.
  33. ↑ 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.
  34. ↑ Münzenberg, G.; Armbruster, P.; Heßberger, F. P.; Hofmann, S.; Poppensieker, K.; Reisdorf, W.; Schneider, J. H. R.; Schneider, W. F. W.; Schmidt, K.-H.; Sahm, C.-C.; Vermeulen, D. (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.
  35. ↑ Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Archived from the original on 2019-04-02. Retrieved 2008-06-06.
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