Chemistry:Darmstadtium

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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.

In the periodic table, it is a d-block transactinide element. It is a member of the 7th period and is placed in the group 10 elements, although no chemical experiments have yet been carried out to confirm that it behaves as the heavier homologue to platinum in group 10 as the eighth member of the 6d series of transition metals. Darmstadtium is calculated to have similar properties to its lighter homologues, nickel, palladium, and platinum.

Introduction

History

The city center of Darmstadt, the namesake of darmstadtium

Discovery

Darmstadtium was first discovered on November 9, 1994, at the Institute for Heavy Ion Research (Gesellschaft für Schwerionenforschung, GSI) in Darmstadt, Germany , by Peter Armbruster and Gottfried Münzenberg, under the direction of Sigurd Hofmann. The team bombarded a lead-208 target with accelerated nuclei of nickel-62 in a heavy ion accelerator and detected a single atom of the isotope darmstadtium-269:[1]

20882Pb + 6228Ni269110Ds + 10n

Two more atoms followed on November 12 and 17.[1] (Yet another was originally reported to have been found on November 11, but it turned out to be based on data fabricated by Victor Ninov, and was then retracted.)[2]

In the same series of experiments, the same team also carried out the reaction using heavier nickel-64 ions. During two runs, 9 atoms of 271Ds were convincingly detected by correlation with known daughter decay properties:[3]

20882Pb + 6428Ni271110Ds + 10n

Prior to this, there had been failed synthesis attempts in 1986–87 at the Joint Institute for Nuclear Research in Dubna (then in the Soviet Union) and in 1990 at the GSI. A 1995 attempt at the Lawrence Berkeley National Laboratory resulted in signs suggesting but not pointing conclusively at the discovery of a new isotope 267Ds formed in the bombardment of 209Bi with 59Co, and a similarly inconclusive 1994 attempt at the JINR showed signs of 273Ds being produced from 244Pu and 34S. Each team proposed its own name for element 110: the American team proposed hahnium after Otto Hahn in an attempt to resolve the controversy of naming element 105 (which they had long been suggesting this name for), the Russian team proposed becquerelium after Henri Becquerel, and the German team proposed darmstadtium after Darmstadt, the location of their institute.[4] The IUPAC/IUPAP Joint Working Party (JWP) recognised the GSI team as discoverers in their 2001 report, giving them the right to suggest a name for the element.[5]

Naming

Using Mendeleev's nomenclature for unnamed and undiscovered elements, darmstadtium should be known as eka-platinum. In 1979, IUPAC published recommendations according to which the element was to be called ununnilium (with the corresponding symbol of Uun),[6] a systematic element name as a placeholder, until the element was discovered (and the discovery then confirmed) and a permanent name was decided on. Although widely used in the chemical community on all levels, from chemistry classrooms to advanced textbooks, the recommendations were mostly ignored among scientists in the field, who called it "element 110", with the symbol of E110, (110) or even simply 110.[7]

In 1996, the Russian team proposed the name becquerelium after Henri Becquerel.[8] The American team in 1997 proposed the name hahnium[9] after Otto Hahn (previously this name had been used for element 105).

The name darmstadtium (Ds) was suggested by the GSI team in honor of the city of Darmstadt, where the element was discovered.[10][11] The GSI team originally also considered naming the element wixhausium, after the suburb of Darmstadt known as Wixhausen where the element was discovered, but eventually decided on darmstadtium.[12] Policium had also been proposed as a joke due to the emergency telephone number in Germany being 1-1-0.[13] The new name darmstadtium was officially recommended by IUPAC on August 16, 2003.[10]

Isotopes

Main page: Physics:Isotopes of darmstadtium
List of darmstadtium isotopes
Isotope Half-life[lower-alpha 1] Decay
mode
Discovery
year[14]
Discovery
reaction[15]
Value Ref
267Ds[lower-alpha 2] 000000010 10 µs [14] α 1994 209Bi(59Co,n)
269Ds 230 230 µs [14] α 1994 208Pb(62Ni,n)
270Ds 205 205 µs [14] α 2000 207Pb(64Ni,n)
270mDs 10000 10 ms [14] α 2000 207Pb(64Ni,n)
271Ds 90000 90 ms [14] α 1994 208Pb(64Ni,n)
271mDs 1700 1.7 ms [14] α 1994 208Pb(64Ni,n)
273Ds 240 240 µs [14] α 1996 244Pu(34S,5n)[16]
275Ds 62 62 µs [17] α 2023 232Th(48Ca,5n)
276Ds 150 150 µs [18] SF, α 2022 232Th(48Ca,4n)[18]
277Ds 3500 3.5 ms [19] α 2010 285Fl(—,2α)
279Ds 186000 186 ms [20] SF, α 2003 287Fl(—,2α)
280Ds[21] 360 360 µs [22][23][24] SF 2021 288Fl(—,2α)
281Ds 14000000 14 s [25] SF, α 2004 289Fl(—,2α)
281mDs[lower-alpha 2] 900000 900 ms [14] α 2012 293mLv(—,3α)


Darmstadtium has no stable or naturally occurring isotopes. Several radioactive isotopes have been synthesized in the laboratory, either by fusing two atoms or by observing the decay of heavier elements. Eleven different isotopes of darmstadtium have been reported with atomic masses 267, 269–271, 273, 275–277, and 279–281, although darmstadtium-267 is unconfirmed. Three darmstadtium isotopes, darmstadtium-270, darmstadtium-271, and darmstadtium-281, have known metastable states, although that of darmstadtium-281 is unconfirmed.[26] Most of these decay predominantly through alpha decay, but some undergo spontaneous fission.[27]

Stability and half-lives

This chart of decay modes according to the model of the Japan Atomic Energy Agency predicts several superheavy nuclides within the island of stability having total half-lives exceeding one year (circled) and undergoing primarily alpha decay, peaking at 294Ds with an estimated half-life of 300 years.[28]

All darmstadtium isotopes are extremely unstable and radioactive; in general, the heavier isotopes are more stable than the lighter. The most stable known darmstadtium isotope, 281Ds, is also the heaviest known darmstadtium isotope; it has a half-life of 14 seconds. The isotope 279Ds has a half-life of 0.18 seconds, while the unconfirmed 281mDs has a half-life of 0.9 seconds. The remaining isotopes and metastable states have half-lives between 1 microsecond and 70 milliseconds.[27] Some unknown darmstadtium isotopes may have longer half-lives, however.[29]

Theoretical calculation in a quantum tunneling model reproduces the experimental alpha decay half-life data for the known darmstadtium isotopes.[30][31] It also predicts that the undiscovered isotope 294Ds, which has a magic number of neutrons (184),[7] would have an alpha decay half-life on the order of 311 years; exactly the same approach predicts a ~350-year alpha half-life for the non-magic 293Ds isotope, however.[29][32]

Predicted properties

Other than nuclear properties, no properties of darmstadtium or its compounds have been measured; this is due to its extremely limited and expensive production[33] and the fact that darmstadtium (and its parents) decays very quickly. Properties of darmstadtium metal remain unknown and only predictions are available.

Chemical

Darmstadtium is the eighth member of the 6d series of transition metals, and should be much like the platinum group metals.[11] Calculations on its ionization potentials and atomic and ionic radii are similar to that of its lighter homologue platinum, thus implying that darmstadtium's basic properties will resemble those of the other group 10 elements, nickel, palladium, and platinum.[7]

Prediction of the probable chemical properties of darmstadtium has not received much attention recently. Darmstadtium should be a very noble metal. The predicted standard reduction potential for the Ds2+/Ds couple is 1.7 V.[7] Based on the most stable oxidation states of the lighter group 10 elements, the most stable oxidation states of darmstadtium are predicted to be the +6, +4, and +2 states; however, the neutral state is predicted to be the most stable in aqueous solutions. In comparison, only platinum is known to show the maximum oxidation state in the group, +6, while the most stable state is +2 for both nickel and palladium. It is further expected that the maximum oxidation states of elements from bohrium (element 107) to darmstadtium (element 110) may be stable in the gas phase but not in aqueous solution.[7] Darmstadtium hexafluoride (DsF6) is predicted to have very similar properties to its lighter homologue platinum hexafluoride (PtF6), having very similar electronic structures and ionization potentials.[7][34][35] It is also expected to have the same octahedral molecular geometry as PtF6.[36] Other predicted darmstadtium compounds are darmstadtium carbide (DsC) and darmstadtium tetrachloride (DsCl4), both of which are expected to behave like their lighter homologues.[36] Unlike platinum, which preferentially forms a cyanide complex in its +2 oxidation state, Pt(CN)2, darmstadtium is expected to preferentially remain in its neutral state and form Ds(CN)2−2 instead, forming a strong Ds–C bond with some multiple bond character.[37]

Physical and atomic

Darmstadtium is expected to be a solid under normal conditions and to crystallize in the body-centered cubic structure, unlike its lighter congeners which crystallize in the face-centered cubic structure, because it is expected to have different electron charge densities from them.[38] It should be a very heavy metal with a density of around 26–27 g/cm3. In comparison, the densest known element that has had its density measured, osmium, has a density of only 22.61 g/cm3.[39][40]

The outer electron configuration of darmstadtium is calculated to be 6d8 7s2, which obeys the Aufbau principle and does not follow platinum's outer electron configuration of 5d9 6s1. This is due to the relativistic stabilization of the 7s2 electron pair over the whole seventh period, so that none of the elements from 104 to 112 are expected to have electron configurations violating the Aufbau principle. The atomic radius of darmstadtium is expected to be around 132 pm.[7]

Experimental chemistry

Unambiguous determination of the chemical characteristics of darmstadtium has yet to have been established[41] due to the short half-lives of darmstadtium isotopes and a limited number of likely volatile compounds that could be studied on a very small scale. One of the few darmstadtium compounds that are likely to be sufficiently volatile is darmstadtium hexafluoride (DsF6), as its lighter homologue platinum hexafluoride (PtF6) is volatile above 60 °C and therefore the analogous compound of darmstadtium might also be sufficiently volatile;[11] a volatile octafluoride (DsF8) might also be possible.[7] For chemical studies to be carried out on a transactinide, at least four atoms must be produced, the half-life of the isotope used must be at least 1 second, and the rate of production must be at least one atom per week.[11] Even though the half-life of 281Ds, the most stable confirmed darmstadtium isotope, is 14 seconds, long enough to perform chemical studies, another obstacle is the need to increase the rate of production of darmstadtium isotopes and allow experiments to carry on for weeks or months so that statistically significant results can be obtained. Separation and detection must be carried out continuously to separate out the darmstadtium isotopes and have automated systems experiment on the gas-phase and solution chemistry of darmstadtium, as the yields for heavier elements are predicted to be smaller than those for lighter elements; some of the separation techniques used for bohrium and hassium could be reused. However, the experimental chemistry of darmstadtium has not received as much attention as that of the heavier elements from copernicium to livermorium.[7][41][42]

The more neutron-rich darmstadtium isotopes are the most stable[27] and are thus more promising for chemical studies.[7][11] However, they can only be produced indirectly from the alpha decay of heavier elements,[43][44][45] and indirect synthesis methods are not as favourable for chemical studies as direct synthesis methods.[7] The more neutron-rich isotopes 276Ds and 277Ds might be produced directly in the reaction between thorium-232 and calcium-48, but the yield was expected to be low.[7][46][47] Following several unsuccessful attempts, 276Ds was produced in this reaction in 2022 and observed to have a half-life less than a millisecond and a low yield, in agreement with predictions.[18] Additionally, 277Ds was successfully synthesized using indirect methods (as a granddaughter of 285Fl) and found to have a short half-life of 3.5 ms, not long enough to perform chemical studies.[19][44] The only known darmstadtium isotope with a half-life long enough for chemical research is 281Ds, which would have to be produced as the granddaughter of 289Fl.[48]

See also

Notes

  1. Different sources give different values for half-lives; the most recently published values are listed.
  2. 2.0 2.1 This isotope is unconfirmed

References

  1. 1.0 1.1 Hofmann, S.; Ninov, V.; Heßberger, F. P.; Armbruster, P.; Folger, H.; Münzenberg, G.; Schött, H. J.; Popeko, A. G. et al. (1995). "Production and decay of 269110". Zeitschrift für Physik A 350 (4): 277. doi:10.1007/BF01291181. Bibcode1995ZPhyA.350..277H. 
  2. Dalton, Rex (2002). "California lab fires physicist over retracted finding". Nature 418 (6895): 261. doi:10.1038/418261b. PMID 12124581. Bibcode2002Natur.418..261D. 
  3. Hofmann, S (1998). "New elements – approaching". Reports on Progress in Physics 61 (6): 639. doi:10.1088/0034-4885/61/6/002. Bibcode1998RPPh...61..639H. 
  4. Barber, R. C.; Greenwood, N. N.; Hrynkiewicz, A. Z.; Jeannin, Y. P.; Lefort, M.; Sakai, M.; Ulehla, I.; Wapstra, A. P. et al. (1993). "Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements". Pure and Applied Chemistry 65 (8): 1757. doi:10.1351/pac199365081757.  (Note: for Part I see Pure Appl. Chem., Vol. 63, No. 6, pp. 879–886, 1991)
  5. Karol, P. J.; Nakahara, H.; Petley, B. W.; Vogt, E. (2001). "On the discovery of the elements 110–112 (IUPAC Technical Report)". Pure and Applied Chemistry 73 (6): 959. doi:10.1351/pac200173060959. 
  6. Chatt, J. (1979). "Recommendations for the naming of elements of atomic numbers greater than 100". Pure and Applied Chemistry 51 (2): 381–384. doi:10.1351/pac197951020381. 
  7. 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 7.11 Cite error: Invalid <ref> tag; no text was provided for refs named Haire
  8. "Chemistry : Periodic Table : darmstadtium : historical information". January 17, 2005. http://element114.narod.ru/110-history.html. 
  9. Albert, Ghiorso; Darleane, Hoffman C; Glenn, Seaborg T (2000-01-21). Transuranium People, The: The Inside Story. World Scientific. ISBN 9781783262441. https://books.google.com/books?id=yP63CgAAQBAJ&q=element+110+hahnium&pg=PA397. 
  10. 10.0 10.1 Corish, J.; Rosenblatt, G. M. (2003). "Name and symbol of the element with atomic number 110". Pure Appl. Chem. 75 (10): 1613–1615. doi:10.1351/pac200375101613. http://pac.iupac.org/publications/pac/pdf/2003/pdf/7510x1613.pdf. Retrieved 17 October 2012. 
  11. 11.0 11.1 11.2 11.3 11.4 Griffith, W. P. (2008). "The Periodic Table and the Platinum Group Metals". Platinum Metals Review 52 (2): 114–119. doi:10.1595/147106708X297486. 
  12. "Chemistry in its element – darmstadtium". Royal Society of Chemistry. http://www.rsc.org/chemistryworld/podcast/interactive_periodic_table_transcripts/darmstadtium.asp. 
  13. Hofmann, Sigurd (2003). On Beyond Uranium: Journey to the End of the Periodic Table. Taylor & Francis. p. 177. ISBN 9780203300985. 
  14. 14.0 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties". Chinese Physics C 41 (3): 030001. doi:10.1088/1674-1137/41/3/030001. Bibcode2017ChPhC..41c0001A. https://www-nds.iaea.org/amdc/ame2016/NUBASE2016.pdf. 
  15. Thoennessen, M. (2016). The Discovery of Isotopes: A Complete Compilation. Springer. pp. 229, 234, 238. doi:10.1007/978-3-319-31763-2. ISBN 978-3-319-31761-8. 
  16. Lazarev, Yu. A.; Lobanov, Yu.; Oganessian, Yu.; Utyonkov, V.; Abdullin, F.; Polyakov, A.; Rigol, J.; Shirokovsky, I. et al. (1996). "α decay of 273110: Shell closure at N=162". Physical Review C 54 (2): 620–625. doi:10.1103/PhysRevC.54.620. PMID 9971385. Bibcode1996PhRvC..54..620L. 
  17. "New darmstadtium isotope discovered at Superheavy Element Factory". Joint Institute for Nuclear Research. 27 February 2023. http://www.jinr.ru/posts/new-darmstadtium-isotope-discovered-at-superheavy-element-factory/. 
  18. 18.0 18.1 18.2 Oganessian, Yu. Ts.Expression error: Unrecognized word "et". (2023). "New isotope 276Ds and its decay products 272Hs and 268Sg from the 232Th + 48Ca reaction". Physical Review C 108 (24611): 024611. doi:10.1103/PhysRevC.108.024611. Bibcode2023PhRvC.108b4611O. 
  19. 19.0 19.1 Utyonkov, V. K.; Brewer, N. T.; Oganessian, Yu. Ts.; Rykaczewski, K. P.; Abdullin, F. Sh.; Dimitriev, S. N.; Grzywacz, R. K.; Itkis, M. G. et al. (30 January 2018). "Neutron-deficient superheavy nuclei obtained in the 240Pu+48Ca reaction". Physical Review C 97 (14320): 014320. doi:10.1103/PhysRevC.97.014320. Bibcode2018PhRvC..97a4320U. 
  20. Oganessian, Yu. Ts.Expression error: Unrecognized word "et". (2022). "Investigation of 48Ca-induced reactions with 242Pu and 238U targets at the JINR Superheavy Element Factory". Physical Review C 106 (24612): 024612. doi:10.1103/PhysRevC.106.024612. Bibcode2022PhRvC.106b4612O. 
  21. Forsberg, U. (2016). "Recoil-α-fission and recoil-α-α-fission events observed in the reaction 48Ca + 243Am". Nuclear Physics A 953: 117–138. doi:10.1016/j.nuclphysa.2016.04.025. Bibcode2016NuPhA.953..117F. 
  22. Morita, K. (2014). "Measurement of the 248Cm + 48Ca fusion reaction products at RIKEN GARIS". RIKEN Accel. Prog. Rep. 47: xi. http://www.nishina.riken.jp/researcher/APR/APR047/pdf/xi.pdf. 
  23. Kaji, Daiya; Morita, Kosuke; Morimoto, Kouji; Haba, Hiromitsu; Asai, Masato; Fujita, Kunihiro; Gan, Zaiguo; Geissel, Hans et al. (2017). "Study of the Reaction 48Ca + 248Cm → 296Lv* at RIKEN-GARIS". Journal of the Physical Society of Japan 86 (3): 034201–1–7. doi:10.7566/JPSJ.86.034201. Bibcode2017JPSJ...86c4201K. 
  24. Såmark-Roth, A.; Cox, D. M.; Rudolph, D.; Sarmento, L. G.; Carlsson, B. G.; Egido, J. L.; Golubev, P; Heery, J. et al. (2021). "Spectroscopy along Flerovium Decay Chains: Discovery of 280Ds and an Excited State in 282Cn". Physical Review Letters 126 (3): 032503. doi:10.1103/PhysRevLett.126.032503. PMID 33543956. Bibcode2021PhRvL.126c2503S. 
  25. Oganessian, Y.T. (2015). "Super-heavy element research". Reports on Progress in Physics 78 (3): 036301. doi:10.1088/0034-4885/78/3/036301. PMID 25746203. Bibcode2015RPPh...78c6301O. https://www.researchgate.net/publication/273327193. 
  26. Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Khuyagbaatar, J.; Ackermann, D.; Antalic, S.; Barth, W. et al. (2012). "The reaction 48Ca + 248Cm → 296116* studied at the GSI-SHIP". The European Physical Journal A 48 (5): 62. doi:10.1140/epja/i2012-12062-1. Bibcode2012EPJA...48...62H. 
  27. 27.0 27.1 27.2 Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. http://www.nndc.bnl.gov/chart/reCenter.jsp?z=110&n=163. 
  28. Koura, H. (2011). "Decay modes and a limit of existence of nuclei in the superheavy mass region". 4th International Conference on the Chemistry and Physics of the Transactinide Elements. http://tan11.jinr.ru/pdf/10_Sep/S_2/05_Koura.pdf. Retrieved 18 November 2018. 
  29. 29.0 29.1 P. Roy Chowdhury; C. Samanta; D. N. Basu (2008). "Search for long lived heaviest nuclei beyond the valley of stability". Phys. Rev. C 77 (4): 044603. doi:10.1103/PhysRevC.77.044603. Bibcode2008PhRvC..77d4603C. 
  30. P. Roy Chowdhury; C. Samanta; D. N. Basu (2006). "α decay half-lives of new superheavy elements". Phys. Rev. C 73 (1): 014612. doi:10.1103/PhysRevC.73.014612. Bibcode2006PhRvC..73a4612C. 
  31. C. Samanta; P. Roy Chowdhury; D.N. Basu (2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nucl. Phys. A 789 (1–4): 142–154. doi:10.1016/j.nuclphysa.2007.04.001. Bibcode2007NuPhA.789..142S. 
  32. P. Roy Chowdhury; C. Samanta; D. N. Basu (2008). "Nuclear half-lives for α -radioactivity of elements with 100 ≤ Z ≤ 130". Atomic Data and Nuclear Data Tables 94 (6): 781–806. doi:10.1016/j.adt.2008.01.003. Bibcode2008ADNDT..94..781C. 
  33. Subramanian, S.. "Making New Elements Doesn't Pay. Just Ask This Berkeley Scientist". https://www.bloomberg.com/news/features/2019-08-28/making-new-elements-doesn-t-pay-just-ask-this-berkeley-scientist. 
  34. Rosen, A.; Fricke, B.; Morovic, T.; Ellis, D. E. (1979). "Relativistic molecular calculations of superheavy molecules". Journal de Physique Colloques 40: C4–218–C4–219. doi:10.1051/jphyscol:1979467. http://nbn-resolving.org/urn:nbn:de:hebis:34-2008091023676. 
  35. Waber, J. T.; Averill, F. W. (1974). "Molecular orbitals of PtF6 and E110 F6 calculated by the self-consistent multiple scattering Xα method". J. Chem. Phys. 60 (11): 4460–70. doi:10.1063/1.1680924. Bibcode1974JChPh..60.4466W. 
  36. 36.0 36.1 Thayer, John S. (2010), "Relativistic Effects and the Chemistry of the Heavier Main Group Elements", Relativistic Methods for Chemists, Challenges and Advances in Computational Chemistry and Physics, 10, p. 82, doi:10.1007/978-1-4020-9975-5_2, ISBN 978-1-4020-9974-8 
  37. Demissie, Taye B.; Ruud, Kenneth (25 February 2017). "Darmstadtium, roentgenium, and copernicium form strong bonds with cyanide". International Journal of Quantum Chemistry 2017: e25393. doi:10.1002/qua.25393. https://munin.uit.no/bitstream/10037/13632/4/article.pdf. 
  38. Cite error: Invalid <ref> tag; no text was provided for refs named bcc
  39. Cite error: Invalid <ref> tag; no text was provided for refs named density
  40. Cite error: Invalid <ref> tag; no text was provided for refs named kratz
  41. 41.0 41.1 Düllmann, Christoph E. (2012). "Superheavy elements at GSI: a broad research program with element 114 in the focus of physics and chemistry". Radiochimica Acta 100 (2): 67–74. doi:10.1524/ract.2011.1842. 
  42. Eichler, Robert (2013). "First foot prints of chemistry on the shore of the Island of Superheavy Elements". Journal of Physics: Conference Series 420 (1): 012003. doi:10.1088/1742-6596/420/1/012003. Bibcode2013JPhCS.420a2003E. 
  43. Oganessian, Y. T.; Utyonkov, V.; Lobanov, Y.; Abdullin, F.; Polyakov, A.; Shirokovsky, I.; Tsyganov, Y.; Gulbekian, G. 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. doi:10.1103/PhysRevC.69.054607. Bibcode2004PhRvC..69e4607O. http://link.aps.org/abstract/PRC/V69/E054607/. 
  44. 44.0 44.1 Public Affairs Department (26 October 2010). "Six New Isotopes of the Superheavy Elements Discovered: Moving Closer to Understanding the Island of Stability". Berkeley Lab. http://newscenter.lbl.gov/news-releases/2010/10/26/six-new-isotopes. 
  45. Yeremin, A. V. (1999). "Synthesis of nuclei of the superheavy element 114 in reactions induced by 48Ca". Nature 400 (6741): 242–245. doi:10.1038/22281. Bibcode1999Natur.400..242O. 
  46. "JINR Publishing Department: Annual Reports (Archive)". http://www1.jinr.ru/Reports/Reports_eng_arh.html. 
  47. Feng, Z; Jin, G.; Li, J.; Scheid, W. (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A 816 (1): 33. doi:10.1016/j.nuclphysa.2008.11.003. Bibcode2009NuPhA.816...33F. 
  48. Moody, Ken (2013-11-30). "Synthesis of Superheavy Elements". in Schädel, Matthias; Shaughnessy, Dawn. The Chemistry of Superheavy Elements (2nd ed.). Springer Science & Business Media. pp. 24–8. ISBN 9783642374661. 

Bibliography

External links

  • Darmstadtium at The Periodic Table of Videos (University of Nottingham)