Isotopes of hassium

Hassium (Hs) is a synthetic element, and thus a standard atomic mass cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 265Hs in 1984. There are 12 known isotopes from 263Hs to 277Hs and 1–4 isomers. The longest-lived isotope is 269Hs with a half-life of 9.6 seconds.

Table

nuclide
symbol		 Z(p) N(n)  
Isotopic mass (u)
 		 Half-life Decay
mode(s)		 Daughter
isotope(s)		 Nuclear
spin
Excitation energy
263Hs 108 155 263.12856(37)[lower-alpha 1] 760(40) µs α 259Sg 7/2+[lower-alpha 1]
264Hs 108 156 264.12836(3) 540(300) µs α (50%) 260Sg 0+
SF[lower-alpha 2] (50%) (various)
265Hs 108 157 265.129793(26) 1.96(0.16) ms α 261Sg 9/2+[lower-alpha 1]
265mHs 300(70) keV 360(150) µs α 261Sg 3/2+[lower-alpha 1]
266Hs[lower-alpha 3] 108 158 266.13005(4) 3.02(0.54) ms α (68%) 262Sg 0+
SF (32%)[1] (various)
266mHs 1100(70) keV 280(220) ms α 262Sg 9-[lower-alpha 1]
267Hs 108 159 267.13167(10)[lower-alpha 1] 55(11) ms α 263Sg 5/2+[lower-alpha 1]
267mHs[lower-alpha 4] 39(24) keV 990(90) µs α 263Sg
268Hs 108 160 268.13187(30)[lower-alpha 1] 1.42(1.13) s α 264Sg 0+
269Hs[lower-alpha 5] 108 161 269.13375(13)[lower-alpha 1] 27(17) s α 265Sg 9/2+[lower-alpha 1]
270Hs 108 162 270.13429(27)[lower-alpha 1] 3.6(+8-14) s α 266Sg 0+
271Hs 108 163 271.13717(32)[lower-alpha 1] ~4 s α 267Sg
273Hs[lower-alpha 6] 108 165 273.14168(40)[lower-alpha 1] 760 ms[2] α 269Sg 3/2+[lower-alpha 1]
275Hs[lower-alpha 7] 108 167 275.14667(63)[lower-alpha 1] 290(150) ms α 271Sg
277Hs[lower-alpha 8] 108 169 277.15190(58)[lower-alpha 1] 11(9) ms SF[lower-alpha 2] (various) 3/2+[lower-alpha 1]
277mHs[lower-alpha 4][lower-alpha 8] 100(100) keV[lower-alpha 1] 130(100) s SF[lower-alpha 2] (various)

Notes

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Values not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
  2. 1 2 3 Spontaneous fission
  3. ↑ Not directly synthesized, occurs as decay product of 270Ds
  4. 1 2 Existence of this isomer is unconfirmed
  5. ↑ Not directly synthesized, occurs in decay chain of 277Cn
  6. ↑ Not directly synthesized, occurs in decay chain of 285Fl
  7. ↑ Not directly synthesized, occurs in decay chain of 287Fl
  8. 1 2 Not directly synthesized, occurs in decay chain of 289Fl

Isotopes and nuclear properties

Target-projectile combinations leading to Z=108 compound nuclei

TargetProjectileCNAttempt result
136Xe 136Xe272HsFailure to date
198Pt 70Zn268HsFailure to date
208Pb 58Fe266HsSuccessful reaction
207Pb 58Fe265HsSuccessful reaction
208Pb 56Fe264HsSuccessful reaction
207Pb 56Fe263HsReaction yet to be attempted
206Pb 58Fe264HsSuccessful reaction
209Bi 55Mn264HsFailure to date
226Ra 48Ca274HsSuccessful reaction
228Ra 48Ca276HsReaction yet to be attempted
232Th 40Ar272HsFailure to date
238U 36S274HsSuccessful reaction
238U 34S272HsSuccessful reaction
239Pu 30Si269HsReaction yet to be attempted
244Pu 30Si274HsReaction yet to be attempted
244Pu 32Si276HsReaction yet to be attempted
248Cm 26Mg274HsSuccessful reaction
248Cm 25Mg273HsFailure to date
250Cm 26Mg276HsReaction yet to be attempted
249Cf 22Ne271HsSuccessful reaction
252Cf 22Ne274HsReaction yet to be attempted
257Fm 18O275HsReaction yet to be attempted

Nucleosynthesis

Super-heavy elements such as hassium are produced by bombarding lighter elements in particle accelerators that induce fusion reactions. Whereas most of the isotopes of hassium can be synthesized directly this way, some heavier ones have only been observed as decay products of elements with higher atomic numbers.[3]

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.[4] 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.[3] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).[5]

Cold fusion

Before the first successful synthesis of hassium in 1984 by the GSI team, scientists at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia also tried to synthesize hassium by bombarding lead-208 with iron-58 in 1978. No hassium atoms were identified. They repeated the experiment in 1984 and were able to detect a spontaneous fission activity assigned to 260Sg, the daughter of 264Hs.[6] Later that year, they tried the experiment again, and tried to chemically identify the decay products of hassium to provide support to their synthesis of element 108. They were able to detect several alpha decays of 253Es and 253Fm, decay products of 265Hs.[7]

In the official discovery of the element in 1984, the team at GSI studied the same reaction using the alpha decay genetic correlation method and were able to positively identify 3 atoms of 265Hs.[8] After an upgrade of their facilities in 1993, the team repeated the experiment in 1994 and detected 75 atoms of 265Hs and 2 atoms of 264Hs, during the measurement of a partial excitation function for the 1n neutron evaporation channel.[9] A further run of the reaction was conducted in late 1997 in which a further 20 atoms were detected.[10] This discovery experiment was successfully repeated in 2002 at RIKEN (10 atoms) and in 2003 at GANIL (7 atoms). The team at RIKEN further studied the reaction in 2008 in order to conduct the first spectroscopic studies of the even-even nucleus 264Hs. They were also able to detect a further 29 atoms of 265Hs.

The team at Dubna also conducted the analogous reaction with a lead-207 target instead of a lead-208 target in 1984:

207
82Pb
 + 58
26Fe
 → 264
108Hs
 +
n

They were able to detect the same spontaneous fission activity as observed in the reaction with a lead-208 target and once again assigned it to 260Sg, daughter of 264Hs.[7] The team at GSI first studied the reaction in 1986 using the method of genetic correlation of alpha decays and identified a single atom of 264Hs with a cross section of 3.2 pb pb pb.[11] The reaction was repeated in 1994 and the team were able to measure both alpha decay and spontaneous fission for 264Hs. This reaction was also studied in 2008 at RIKEN in order to conduct the first spectroscopic studies of the even-even nucleus 264Hs. The team detected 11 atoms of 264Hs.

In 2008, the team at RIKEN conducted the analogous reaction with a lead-206 target for the first time:

206
82Pb
 + 58
26Fe
 → 263
108Hs
 +
n

They were able to identify 8 atoms of the new isotope 263Hs.[12]

In 2008, the team at the Lawrence Berkeley National Laboratory (LBNL) studied the analogous reaction with iron-56 projectiles for the first time:

208
82Pb
 + 56
26Fe
 → 263
108Hs
 +
n

They were able to produce and identify 6 atoms of the new isotope 263Hs.[13] A few months later, the RIKEN team also published their results on the same reaction.[14]

Further attempts to synthesise nuclei of hassium were performed the team at Dubna in 1983 using the cold fusion reaction between a bismuth-209 target and manganese-55 projectiles:

209
83Bi
 + 55
25Mn
 → 264−x
108Hs
 + x
n
 (x = 1 or 2)

They were able to detect a spontaneous fission activity assigned to 255Rf, a product of the 263Hs decay chain. Identical results were measured in a repeat run in 1984.[7] In a subsequent experiment in 1983, they applied the method of chemical identification of a descendant to provide support to the synthesis of hassium. They were able to detect alpha decays from fermium isotopes, assigned as descendants of the decay of 262Hs. This reaction has not been tried since and 262Hs is currently unconfirmed.[7]

Hot fusion

Under the leadership of Yuri Oganessian, the team at the Joint Institute for Nuclear Research studied the hot fusion reaction between calcium-48 projectiles and radium-226 targets in 1978:

226
88Ra
 + 48
20Ca
 → 270
108Hs
 + 4
n

However, results are not available in the literature.[7] The reaction was repeated at the JINR in June 2008 and 4 atoms of the isotope 270Hs were detected.[15] In January 2009, the team repeated the experiment and a further 2 atoms of 270Hs were detected.[16]

The team at Dubna studied the reaction between californium-249 targets and neon-22 projectiles in 1983 by detecting spontaneous fission activities:

249
98Cf
 + 22
10Ne
 → 271−x
108Hs
 + x
n

Several short spontaneous fission activities were found, indicating the formation of nuclei of hassium.[7]

The hot fusion reaction between uranium-238 targets and projectiles of the rare and expensive isotope sulfur-36 was conducted at the GSI in April–May 2008:

238
92U
 + 36
16S
 → 270
108Hs
 + 4
n

Preliminary results show that a single atom of 270Hs was detected. This experiment confirmed the decay properties of the isotopes 270Hs and 266Sg.[17]

In March 1994, the team at Dubna led by the late Yuri Lazarev attempted the analogous reaction with sulfur-34 projectiles:

238
92U
 + 34
16S
 → 272−x
108Hs
 + x
n
 (x = 4 or 5)

They announced the detection of 3 atoms of 267Hs from the 5n neutron evaporation channel.[18] The decay properties were confirmed by the team at GSI in their simultaneous study of darmstadtium. The reaction was repeated at the GSI in January–February 2009 in order to search for the new isotope 268Hs. The team, led by Prof. Nishio, detected a single atom of both 268Hs and 267Hs. The new isotope 268Hs underwent alpha-decay to the previously known isotope 264Sg.

Between May 2001 and August 2005, a GSI-PSI (Paul Scherrer Institute) collaboration studied the nuclear reaction between curium-248 targets and magnesium-26 projectiles:

248
96Cm
 + 26
12Mg
 → 274−x
108Hs
 + x
n
 (x = 3, 4, or 5)

The team studied the excitation function of the 3n, 4n, and 5n evaporation channels leading to the isotopes 269Hs, 270Hs, and 271Hs.[19][20] The synthesis of the important doubly magic isotope 270Hs was published in December 2006 by the team of scientists from the Technical University of Munich.[21] It was reported that this isotope decayed by emission of an alpha particle with an energy of 8.83 MeV and a half-life of ~22 s. This figure has since been revised to 3.6 s.[22]

As decay product

List of hassium isotopes observed by decay
Evaporation residue Observed hassium isotope
267Ds 263Hs[23]
269Ds 265Hs[24]
270Ds 266Hs[25]
271Ds 267Hs[26]
277Cn, 273Ds269Hs[27]
285Fl, 281Cn, 277Ds273Hs[28]
291Lv, 287Fl, 283Cn, 279Ds275Hs[29]
293Lv, 289Fl, 285Cn, 281Ds277Hs[30][31][32]

Hassium has been observed as decay products of darmstadtium. Darmstadtium currently has eight known isotopes, all of which have been shown to undergo alpha decays to become hassium nuclei, with mass numbers between 263 and 277. Hassium isotopes with mass numbers 266, 273, 275, and 277 to date have only been produced by darmstadtium nuclei decay. Parent darmstadtium nuclei can be themselves decay products of copernicium, flerovium, or livermorium. To date, no other elements have been known to decay to hassium.[22] For example, in 2004, the Dubna team identified hassium-277 as a final product in the decay of livermorium via an alpha decay sequence:[32]

293
116Lv
 → 289
114Fl
 + 4
2He
289
114Fl
 → 285
112Cn
 + 4
2He
285
112Cn
 → 281
110Ds
 + 4
2He
281
110Ds
 → 277
108Hs
 + 4
2He

Unconfirmed isotopes

List of hassium isotopes
Isotope
 Half-life
[22] 		Decay
mode[22] 		Discovery
year 		Reaction
263Hs0.74 msα, SF2008208Pb(56Fe,n)[13]
264Hs~0.8 msα, SF1986207Pb(58Fe,n)[11]
265Hs1.9 msα, SF1984208Pb(58Fe,n)[8]
265mHs0.3 msα1984208Pb(58Fe,n)[8]
266Hs2.3 msα, SF2000270Ds(—,α)[25]
267Hs52 msα, SF1995238U(34S,5n)[18]
267mHs0.8 sα1995238U(34S,5n)[18]
268Hs0.4 sα2009238U(34S,4n)
269Hs3.6 sα1996277Cn(—,2α)[27]
269mHs9.7 sα2004248Cm(26Mg,5n)[19]
270Hs3.6 sα2004248Cm(26Mg,4n)[19]
271Hs~4 sα2004248Cm(26Mg,3n)[20]
272Hs40? sα, SF ?unknown—
273Hs0.24 sα2004285Fl(—,3α)[28]
274Hs1? minα, SF ?unknown—
275Hs0.15 sα2003287Fl(—,3α)[29]
276Hs1? hα, SF ?unknown—
277Hs2 sα2009289Fl(—,3α)[30]
277mHs ?~11 min ?α1999289Fl(—,3α)[31]
277mHs

An isotope assigned to 277Hs has been observed on one occasion decaying by SF with a long half-life of ~11 minutes.[33] The isotope is not observed in the decay of the ground state of 281Ds but is observed in the decay from a rare, as yet unconfirmed isomeric level, namely 281mDs. The half-life is very long for the ground state and it is possible that it belongs to an isomeric level in 277Hs. Furthermore, in 2009, the team at the GSI observed a small alpha decay branch for 281Ds producing the nuclide 277Hs decaying by SF in a short lifetime. The measured half-life is close to the expected value for ground state isomer, 277Hs. Further research is required to confirm the production of the isomer.

Retracted isotopes

273Hs

In 1999, American scientists at the University of California, Berkeley, announced that they had succeeded in synthesizing three atoms of 293118.[34] These parent nuclei were reported to have successively emitted three alpha particles to form hassium-273 nuclei, which were claimed to have undergone an alpha decay, emitting alpha particles with decay energies of 9.78 and 9.47 MeV and half-life 1.2 s, but their claim was retracted in 2001.[35] The isotope, however, was produced in 2010 by the same team. The new data matched the previous (fabricated)[36] data.[28]

270Hs: prospects for a deformed doubly magic nucleus

According to macroscopic-microscopic (MM) theory, Z=108 is a deformed proton magic number, in combination with the neutron shell at N=162. This means that such nuclei are permanently deformed in their ground state but have high, narrow fission barriers to further deformation and hence relatively long SF partial half-lives. The SF half-lives in this region are typically reduced by a factor of 109 in comparison with those in the vicinity of the spherical doubly magic nucleus298114, caused by an increase in the probability of barrier penetration by quantum tunnelling, due to the narrower fission barrier. In addition, N=162 has been calculated as a deformed neutron magic number and hence the nucleus 270Hs has promise as a deformed doubly magic nucleus. Experimental data from the decay of Z=110 isotopes 271Ds and 273Ds, provides strong evidence for the magic nature of the N=162 sub-shell. The recent synthesis of 269Hs, 270Hs, and 271Hs also fully support the assignment of N=162 as a magic closed shell. In particular, the low decay energy for 270Hs is in complete agreement with calculations.[37]

Evidence for the Z=108 deformed proton shell

Evidence for the magicity of the Z=108 proton shell can be deemed from two sources:

  1. the variation in the partial spontaneous fission half-lives for isotones
  2. the large gap in Qα for isotonic pairs between Z=108 and Z=110.

For SF, it is necessary to measure the half-lives for the isotonic nuclei 268Sg, 270Hs and 272Ds. Since the seaborgium and darmstadtium isotopes are not known at this time, and fission of 270Hs has not been measured, this method can be used to date to confirm the stabilizing nature of the Z=108 shell. However, good evidence for the magicity of the Z=108 can be deemed from the large differences in the alpha decay energies measured for 270Hs,271Ds and 273Ds. More conclusive evidence would come from the determination of the decay energy for the nucleus 272Ds.

Nuclear isomerism

277Hs

An isotope assigned to 277Hs has been observed on one occasion decaying by spontaneous fission with a long half-life of ~11 minutes.[38] The isotope is not observed in the decay of the most common isomer of 281Ds but is observed in the decay from a rare, as yet unconfirmed isomeric level, namely 281mDs. The half-life is very long for the ground state and it is possible that it belongs to an isomeric level in 277Hs. Furthermore, in 2009, the team at the GSI observed a small alpha decay branch for 281Ds producing an isotope of 277Hs decaying by spontaneous fission with a short lifetime. The measured half-life is close to the expected value for ground state isomer, 277Hs. Further research is required to confirm the production of the isomer.[30]

269Hs

The direct synthesis of 269Hs has resulted in the observation of three alpha particles with energies 9.21, 9.10, and 8.94 MeV emitted from 269Hs atoms. However, when this isotope is indirectly synthesized from the decay of 277Cn, only alpha particles with energy 9.21 MeV have been observed, indicating that this decay occurs from an isomeric level. Further research is required to confirm this.[19][27]

267Hs

267Hs is known to decay by alpha decay, emitting alpha particles with energies of 9.88, 9.83, and 9.75 MeV. It has a half-life of 52 ms. In the recent syntheses of 271Ds and 271mDs, additional activities have been observed. A 0.94 ms activity emitting alpha particles with energy 9.83 MeV has been observed in addition to longer lived ~0.8 s and ~6.0 s activities. Currently, none of these are assigned and confirmed and further research is required to positively identify them.[18]

265Hs

The synthesis of 265Hs has also provided evidence for two isomeric levels. The ground state decays by emission of an alpha particle with energy 10.30 MeV and has a half-life of 2.0 ms. The isomeric state has 300 keV of excess energy and decays by the emission of an alpha particle with energy 10.57 MeV and has a half-life of 0.75 ms.[8]

Future experiments

Scientists at the GSI are planning to search for isomers of 270Hs using the reaction 226Ra(48Ca,4n) in 2010 using the new TASCA facility at the GSI.[39] In addition, they also hope to study the spectroscopy of 269Hs, 265Sg and 261Rf, using the reaction 248Cm(26Mg,5n) or 226Ra(48Ca,5n). This will allow them to determine the level structure in 265Sg and 261Rf and attempt to give spin and parity assignments to the various proposed isomers.[40]

Physical production yields

The tables below provides cross-sections and excitation energies for nuclear reactions that produce isotopes of hassium directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel.

Cold fusion

ProjectileTargetCN1n2n3n
58Fe208Pb266Hs69 pb, 13.9 MeV4.5 pb
58Fe 207Pb 265Hs3.2 pb

Hot fusion

ProjectileTargetCN3n4n5n
48Ca226Ra274Hs 9.0 pb
36S238U274Hs 0.8 pb
34S238U272Hs 2.5 pb, 50.0 MeV
26Mg248Cm274Hs2.5 pb3.0 pb7.0 pb

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) σ max Model Ref
136Xe 136Xe 272Hs 1-4n (271-268Hs) 10−6 pb DNS [41]
238U 34S 272Hs 4n (268Hs) 10 pb DNS [41]

References

  1. ↑ Dieter Ackermann (September 8, 2011). "270Ds and Its Decay Products – Decay Properties and Experimental Masses" (PDF). The 4th International conference on the Chemistry and Physics of Transactinide Elements, 5–11 September, Sochi, Russia.
  2. ↑ V. K. Utyonkov (March 31 – April 2, 2015). "Synthesis of superheavy nuclei at limits of stability: 239,240Pu + 48Ca and 249-251Cf + 48Ca reactions" (PDF). Super Heavy Nuclei International Symposium, Texas A & M University, College Station TX, USA.
  3. 1 2 Armbruster, Peter & Münzenberg, Gottfried (1989). "Creating superheavy elements". Scientific American. 34: 36–42.
  4. ↑ 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.
  5. ↑ 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.
  6. ↑ Oganessian, Yu Ts; Demin, A. G.; Hussonnois, M.; Tretyakova, S. P.; Kharitonov, Yu P.; Utyonkov, V. K.; Shirokovsky, I. V.; Constantinescu, O.; et al. (1984). "On the stability of the nuclei of element 108 with A=263–265". Zeitschrift für Physik A. 319 (2): 215–217. Bibcode:1984ZPhyA.319..215O. doi:10.1007/BF01415635.
  7. 1 2 3 4 5 6 Barber, R. C.; Greenwood, N. N.; Hrynkiewicz, A. Z.; Jeannin, Y. P.; Lefort, M.; Sakai, M.; Ulehla, I.; Wapstra, A. P.; Wilkinson, D. H. (1993). "Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements (Note: for Part I see Pure Appl. Chem., Vol. 63, No. 6, pp. 879–886, 1991)". Pure and Applied Chemistry. 65 (8): 1757. doi:10.1351/pac199365081757.
  8. 1 2 3 4 Münzenberg, G.; Armbruster, P.; Folger, H.; Heßberger, F. P.; Hofmann, S.; Keller, J.; Poppensieker, K.; Reisdorf, W.; et al. (1984). "The identification of element 108". Zeitschrift für Physik A. 317 (2): 235–236. Bibcode:1984ZPhyA.317..235M. doi:10.1007/BF01421260.
  9. ↑ Hofmann, S. (1998). "New elements – approaching". Reports on Progress in Physics. 61 (6): 639–689. Bibcode:1998RPPh...61..639H. doi:10.1088/0034-4885/61/6/002.
  10. ↑ Hofmann, S.; Heßberger, F.P.; Ninov, V.; Armbruster, P.; Münzenberg, G.; Stodel, C.; Popeko, A.G.; Yeremin, A.V.; et al. (1997). "Excitation function for the production of 265 108 and 266 109". Zeitschrift für Physik A. 358 (4): 377–378. Bibcode:1997ZPhyA.358..377H. doi:10.1007/s002180050343.
  11. 1 2 Münzenberg, G.; Armbruster, P.; Berthes, G.; Folger, H.; Heßberger, F. P.; Hofmann, S.; Poppensieker, K.; Reisdorf, W.; et al. (1986). "Evidence for264108, the heaviest known even-even isotope". Zeitschrift für Physik A. 324 (4): 489–490. Bibcode:1986ZPhyA.324..489M. doi:10.1007/BF01290935.
  12. ↑ Mendeleev Symposium. Morita Archived September 27, 2011, at the Wayback Machine.
  13. 1 2 Dragojević, I.; Gregorich, K.; Düllmann, Ch.; Dvorak, J.; Ellison, P.; Gates, J.; Nelson, S.; Stavsetra, L.; Nitsche, H. (2009). "New Isotope 263108". Physical Review C. 79: 011602. Bibcode:2009PhRvC..79a1602D. doi:10.1103/PhysRevC.79.011602.
  14. ↑ Kaji, Daiya; Morimoto, Kouji; Sato, Nozomi; Ichikawa, Takatoshi; Ideguchi, Eiji; Ozeki, Kazutaka; Haba, Hiromitsu; Koura, Hiroyuki; et al. (2009). "Production and Decay Properties of 263108". Journal of the Physical Society of Japan. 78 (3): 035003. Bibcode:2009JPSJ...78c5003K. doi:10.1143/JPSJ.78.035003.
  15. ↑ "Flerov Laboratory of Nuclear Reactions" (PDF).
  16. ↑ Tsyganov, Yu.; Oganessian, Yu.; Utyonkov, V.; Lobanov, Yu.; Abdullin, F.; Shirokovsky, I.; Polyakov, A.; Subbotin, V.; Sukhov, A. (2009-04-07). "Results of 226Ra+48Ca Experiment". Archived from the original on 2009-04-07. Retrieved 2012-12-25.
  17. ↑ Observation of 270Hs in the complete fusion reaction 36S+238U* R. Graeger et al., GSI Report 2008
  18. 1 2 3 4 Lazarev, Yu. A.; Lobanov, YV; Oganessian, YT; Tsyganov, YS; Utyonkov, VK; Abdullin, FS; Iliev, S; Polyakov, AN; et al. (1995). "New Nuclide 267108 Produced by the 238U + 34S Reaction". Physical Review Letters. 75 (10): 1903–1906. Bibcode:1995PhRvL..75.1903L. doi:10.1103/PhysRevLett.75.1903. PMID 10059158.
  19. 1 2 3 4 "Decay properties of 269Hs and evidence for the new nuclide 270Hs", Turler et al., GSI Annual Report 2001. Retrieved 2008-03-01.
  20. 1 2 Dvorak, Jan (2006-09-25). "On the production and chemical separation of Hs (element 108)" (PDF). Technical University of Munich. Archived from the original (PDF) on 2009-02-25. Retrieved 2012-12-23.
  21. ↑ "Doubly magic 270Hs", Turler et al., GSI report, 2006. Retrieved 2008-03-01.
  22. 1 2 3 4 Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Retrieved 2008-06-06.
  23. ↑ Ghiorso, A.; Lee, D.; Somerville, L.; Loveland, W.; Nitschke, J.; Ghiorso, W.; Seaborg, G.; Wilmarth, P.; et al. (1995). "Evidence for the possible synthesis of element 110 produced by the 59Co+209Bi reaction". Physical Review C. 51 (5): R2293. Bibcode:1995PhRvC..51.2293G. doi:10.1103/PhysRevC.51.R2293.
  24. ↑ 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). "Production and decay of 269110". Zeitschrift für Physik A. 350 (4): 277–280. Bibcode:1995ZPhyA.350..277H. doi:10.1007/BF01291181.
  25. 1 2 Hofmann, S.; Heßberger, F. P.; Ackermann, D.; Antalic, S.; Cagarda, P.; Ćwiok, S.; Kindler, B.; Kojouharova, J.; Lommel, B.; Mann, R.; Münzenberg, G.; Popeko, A. G.; Saro, S.; Schött, H. J.; Yeremin, A. V. (2001). "The new isotope 270110 and its decay products 266Hs and 262Sg" (PDF). The European Physical Journal A. 10: 5–10. Bibcode:2001EPJA...10....5H. doi:10.1007/s100500170137.
  26. ↑ Hofmann, S. (1998). "New elements – approaching". Reports on Progress in Physics. 61 (6): 639–689. Bibcode:1998RPPh...61..639H. doi:10.1088/0034-4885/61/6/002.
  27. 1 2 3 Hofmann, S.; et al. (1996). "The new element 112". Zeitschrift für Physik A. 354 (1): 229–230. doi:10.1007/BF02769517.
  28. 1 2 3 Public Affairs Department (26 October 2010). "Six New Isotopes of the Superheavy Elements Discovered: Moving Closer to Understanding the Island of Stability". Berkeley Lab. Retrieved 2011-04-25.
  29. 1 2 Yeremin, A. V.; Oganessian, Yu. Ts.; Popeko, A. G.; Bogomolov, S. L.; Buklanov, G. V.; Chelnokov, M. L.; Chepigin, V. I.; Gikal, B. N.; Gorshkov, V. A.; Gulbekian, G. G.; Itkis, M. G.; Kabachenko, A. P.; Lavrentev, A. Yu.; Malyshev, O. N.; Rohac, J.; Sagaidak, R. N.; Hofmann, S.; Saro, S.; Giardina, G.; Morita, K. (1999). "Synthesis of nuclei of the superheavy element 114 in reactions induced by 48Ca". Nature. 400 (6741): 242–245. Bibcode:1999Natur.400..242O. doi:10.1038/22281.
  30. 1 2 3 Element 114 – Heaviest Element at GSI Observed at TASCA
  31. 1 2 Oganessian, Yu. Ts.; Utyonkov, V.; Lobanov, Yu.; Abdullin, F.; Polyakov, A.; Shirokovsky, I.; Tsyganov, Yu.; Gulbekian, G.; et al. (1999). "Synthesis of Superheavy Nuclei in the 48Ca+ 244Pu Reaction". Physical Review Letters. 83 (16): 3154–3157. Bibcode:1999PhRvL..83.3154O. doi:10.1103/PhysRevLett.83.3154.
  32. 1 2 Oganessian, Yu. Ts.; et al. (2004). "Measurements of cross sections for the fusion-evaporation reactions 244Pu(48Ca,xn)292−x114 and 245Cm(48Ca,xn)293−x116". Physical Review C. 69 (5): 054607. Bibcode:2004PhRvC..69e4607O. doi:10.1103/PhysRevC.69.054607.
  33. ↑ Yu. Ts. Oganessian; V. K. Utyonkov; Yu. V. Lobanov; F. Sh. Abdullin; A. N. Polyakov; I. V. Shirokovsky; Yu. S. Tsyganov; G. G. Gulbekian; S. L. Bogomolov; et al. (October 2000). "Synthesis of superheavy nuclei in 48Ca+244Pu interactions" (PDF). Nuclei Experiment: Physics of Atomic Nuclei. 63 (10): 1679–1687.
  34. ↑ Ninov, V.; et al. (1999). "Observation of Superheavy Nuclei Produced in the Reaction of 86
    Kr
     with 208
    Pb
    ". Physical Review Letters. 83 (6): 1104–1107. Bibcode:1999PhRvL..83.1104N. doi:10.1103/PhysRevLett.83.1104.
  35. ↑ Public Affairs Department (21 July 2001). "Results of element 118 experiment retracted". Berkeley Lab. Retrieved 2008-01-18.
  36. ↑ George Johnson (15 October 2002). "At Lawrence Berkeley, Physicists Say a Colleague Took Them for a Ride". The New York Times.
  37. ↑ Robert Smolanczuk (1997). "Properties of the hypothetical spherical superheavy nuclei". Physical Review C. 56 (2): 812–824. Bibcode:1997PhRvC..56..812S. doi:10.1103/PhysRevC.56.812.
  38. ↑ Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Gulbekian, G. G.; et al. (2000). "Synthesis of superheavy nuclei in 48Ca+244Pu interactions" (PDF). Physics of Atomic Nuclei. 63 (10): 1679–1687. Bibcode:2000PAN....63.1679O. doi:10.1134/1.1320137.
  39. ↑ TASCA in Small Image Mode Spectroscopy Archived March 5, 2012, at the Wayback Machine.
  40. ↑ Hassium spectroscopy experiments at TASCA, A. Yakushev Archived March 5, 2012, at the Wayback Machine.
  41. 1 2 Influence of entrance channels on formation of superheavy nuclei in massive fusion reactions, Zhao-Qing Feng, Jun-Qing Li, Gen-Ming Jin, April 2009
Isotopes of bohrium Isotopes of hassium Isotopes of meitnerium
Table of nuclides
Isotopes of the chemical elements
1
H		 2
He
3
Li		 4
Be		 5
B		 6
C		 7
N		 8
O		 9
F		 10
Ne
11
Na		 12
Mg		 13
Al		 14
Si		 15
P		 16
S		 17
Cl		 18
Ar
19
K		 20
Ca		 21
Sc		 22
Ti		 23
V		 24
Cr		 25
Mn		 26
Fe		 27
Co		 28
Ni		 29
Cu		 30
Zn		 31
Ga		 32
Ge		 33
As		 34
Se		 35
Br		 36
Kr
37
Rb		 38
Sr		 39
Y		 40
Zr		 41
Nb		 42
Mo		 43
Tc		 44
Ru		 45
Rh		 46
Pd		 47
Ag		 48
Cd		 49
In		 50
Sn		 51
Sb		 52
Te		 53
I		 54
Xe
55
Cs		 56
Ba		 1 asterisk 72
Hf		 73
Ta		 74
W		 75
Re		 76
Os		 77
Ir		 78
Pt		 79
Au		 80
Hg		 81
Tl		 82
Pb		 83
Bi		 84
Po		 85
At		 86
Rn
87
Fr		 88
Ra		 2 asterisks 104
Rf		 105
Db		 106
Sg		 107
Bh		 108
Hs		 109
Mt		 110
Ds		 111
Rg		 112
Cn		 113
Nh		 114
Fl		 115
Mc		 116
Lv		 117
Ts		 118
Og
1 asterisk 57
La		 58
Ce		 59
Pr		 60
Nd		 61
Pm		 62
Sm		 63
Eu		 64
Gd		 65
Tb		 66
Dy		 67
Ho		 68
Er		 69
Tm		 70
Yb		 71
Lu
2 asterisks 89
Ac		 90
Th		 91
Pa		 92
U		 93
Np		 94
Pu		 95
Am		 96
Cm		 97
Bk		 98
Cf		 99
Es		 100
Fm		 101
Md		 102
No		 103
Lr
  • Table of nuclides
  • Categories: Isotopes
  • Tables of nuclides
  • Metastable isotopes
  • Isotopes by element
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