Ununoctium 62200 225580178 2008-07-14T12:06:27Z Mpatel 172616 /* Properties */ reworded to shorten {{Infobox ununoctium}} '''Ununoctium''' ({{pronEng|ˌjuːnəˈnɒktiəm}}<ref>{{citeweb|url=http://reference.aol.com/columbia/_a/ununoctium/20051207161909990012|quote=Pronounced yoo'nànŏk`tēàm|title=Ununoctium|publisher= Columbia Encyclopedia|accessdate=2008-01-18}}</ref> or {{IPA|/ˌʌnəˈnɒktiəm/}}), also known as '''[[Mendeleev's predicted elements|eka-radon]]''' or '''element 118''', is the temporary [[International Union of Pure and Applied Chemistry|IUPAC]] [[systematic element name|name]]<ref>{{citejournal|title=Atomic weights of the elements 2005 (IUPAC Technical Report)|joural=Pure Appl. Chem.|year=2006|volume=78|issue=11|pages=2051&ndash;2066|doi=10.1351/pac200678112051|author=M.E. Wieser|journal=Pure and Applied Chemistry}}</ref> for the [[transactinide element]] having the [[atomic number]] 118 and temporary [[chemical symbol|element symbol]] '''Uuo'''. On the [[periodic table (standard)|periodic table]] of the elements, it is a [[p-block]] element and the last one of the [[period 7|7th period]]. Ununoctium is currently the only [[synthetic element|synthetic]] member of [[noble gases|group 18]] and has the highest atomic number and highest [[atomic mass]] assigned to a discovered element. The [[radioactive decay|radioactive]] ununoctium atom is very unstable, and since 2002, only three atoms of the isotope {{SimpleNuclide|Ununoctium|294}} have been detected.<ref>{{citeweb|url=http://discovermagazine.com/2007/jan/physics/article_view?b_start:int=1&-C=|title=The Top 6 Physics Stories of 2006|accessdate=2008-01-18|date=2007-01-07|publisher=Discover Magazine}}</ref> While this allowed for very little experimental characterization of its properties and its [[noble gas compounds|compounds]], theoretical calculations have allowed for many predictions, including some very unexpected ones. For example, although ununoctium is a member of the ''[[noble gas]] group'', it could have a higher [[chemical reactivity]] than some elements outside this group.<ref name=Nash/> Furthermore, it is predicted that it might not even be a [[gas]] under [[standard conditions for temperature and pressure|normal conditions]].<ref name=Nash/><ref name=note/> ==History== {{seealso|Discoveries of the chemical elements}} ===Unsuccessful attempts=== In late 1998, Polish physicist Robert Smolanczuk published calculations on the fusion of atomic nuclei towards the synthesis of [[superheavy element|superheavy atoms]], including element 118.<ref name=Smolanczuk>{{citejournal|author=Robert Smolanczuk|journal=[[Physical Review]] C|volume=59|issue=5|year=1999|month=5|title=Production mechanism of superheavy nuclei in cold fusion reactions|pages=2634–2639|doi=10.1103/PhysRevC.59.2634}}</ref> His calculations suggested that it might be possible to make element 118 by fusing [[lead]] with [[krypton]] under carefully controlled conditions.<ref name=Smolanczuk/> In 1999, researchers at [[Lawrence Berkeley National Laboratory]] made use of these predictions and announced the discovery of elements [[ununhexium|116]] and 118, in a paper published in ''[[Physical Review Letters]]'',<ref>{{citejournal|last = Ninov|first = Viktor|coauthors = K. E. Gregorich, W. Loveland, A. Ghiorso, D. C. Hoffman, D. M. Lee, H. Nitsche, W. J. Swiatecki, U. W. Kirbach, C. A. Laue, J. L. Adams, J. B. Patin, D. A. Shaughnessy, D. A. Strellis, and P. A. Wilk|title = Observation of Superheavy Nuclei Produced in the Reaction of {{SimpleNuclide|Link|Krypton|86}} with {{SimpleNuclide|Link|Lead|208}}|journal = [[Physical Review Letters]]|volume = 83|issue = 6–9|pages = 1104–1107|date = 1999-05-27|doi = 10.1103/PhysRevLett.83.1104}}</ref> and very soon after the results were reported in ''[[Science (journal)|Science]]''.<ref>{{citejournal|author=Robert F. Service|journal=Science|date=1999-06-11|volume=284|number=5421|pages=1751|doi=10.1126/science.284.5421.1751|title=Berkeley Crew Bags Element 118}}</ref> The researchers claimed to have performed the [[chemical reaction|reaction]] :{{Nuclide|Krypton|86}} + {{Nuclide|Lead|208}} &rarr; {{Nuclide|Ununoctium|293}} + {{SubatomicParticle|link=yes|Neutron}} The following year, they published a retraction after other researchers were unable to duplicate the results.<ref>{{citenews|url=http://enews.lbl.gov/Science-Articles/Archive/118-retraction.html|publisher=Berkeley Lab|author=Public Affairs Department |title=Results of element 118 experiment retracted|date=2001-07-21|accessdate=2008-01-18}}</ref> In June 2002, the director of the lab announced that the original claim of the discovery of these two elements had been based on data fabricated by principal author [[Victor Ninov]].<ref>{{citejournal|first=Dalton|last=Rex|pages=728–729|title=Misconduct: The stars who fell to Earth|journal=[[Nature (journal)|''Nature'']]|volume=420|doi=10.1038/420728a|year=2002}}</ref> ===Discovery === On [[October 9]], [[2006]], researchers from [[Joint Institute for Nuclear Research]] (JINR) and [[Lawrence Livermore National Laboratory]] of California, USA, working at the JINR in [[Dubna]], [[Russia]], announced in ''[[Physical Review]] C''<ref name="full"/> that they had indirectly detected a total of three nuclei of ununoctium-294 (one in 2002<ref>{{citeweb|url=http://159.93.28.88/linkc/118/anno.html|title=Element 118: results from the first {{SimpleNuclide|Californium|249}} + {{SimpleNuclide|Calcium|48}} experiment|author=Oganessian Yu.Ts. et al.|publisher=Communication of the Joint Institute for Nuclear Research|year=2002|publisher+JINR Publishing Department|accessdate=2008-01-18}}</ref> and two more in 2005) produced via collisions of [[californium]]-249 atoms and [[calcium-48]] ions:<ref>{{citenews|title=Livermore scientists team with Russia to discover element 118|url=https://publicaffairs.llnl.gov/news/news_releases/2006/NR-06-10-03.html|publisher=Livermore press release|date=2006-12-03|accessdate=2008-01-18}}</ref><ref>{{citejournal|author=Yu. Ts. Oganessian|title=Synthesis and decay properties of superheavy elements|journal=Pure Appl. Chem.|volume=78|pages=889–904|doi=10.1351/pac200678050889|year=2002}}</ref><ref>{{citenews|title=Heaviest element made - again|work=Nature News|publisher=[[Nature (journal)]]|date=2006-10-17|url=http://www.nature.com/news/2006/061016/full/061016-4.html|accessdate=2008-01-18}}</ref><ref>{{citeweb|author=Phil Schewe|coauthor=Ben Stein|title=Elements 116 and 118 Are Discovered|work=Physics News Update|publisher=[[American Institute of Physics]]|date=2006-10-17|url=http://www.aip.org/pnu/2006/797.html|accessdate=2008-01-18}}</ref><ref>{{citeweb|url=http://www.washingtonpost.com/wp-dyn/content/article/2006/10/16/AR2006101601083.html|title=Scientists Announce Creation of Atomic Element, the Heaviest Yet|publisher=[[Washington Post]]|author=Rick Weiss|date=2006-10-17|accessdate=2008-01-18}}</ref> : {{Nuclide|Link|Californium|249}} + {{Nuclide|Link|Calcium|48}} &rarr; {{Nuclide|Link|Ununoctium|294}} + 3 {{SubatomicParticle|link=yes|Neutron}} [[Image:Ununoctium-294 nuclear.png‎|thumb|left|200px|[[Radioactive decay]] pathway of [[isotope]] Uuo-294.<ref name="full"/> The [[decay energy]] and average [[halflife]] is given for the [[parent isotope]] and each [[daughter isotope]]s. The fraction of atoms undergoing [[spontaneous fission]] (SF) is given in green.]] Because of the very small [[fusion reaction]] probability (the fusion [[nuclear cross section|cross section]] is 0.5 pb = 5×10<sup>−41</sup> m<sup>2</sup>) the experiment took 4 months and involved a beam dose of 4×10<sup>19</sup> [[calcium]] ions that had to be shot at the [[californium]] target to produce the first recorded event believed to be the synthesis of ununoctium.<ref name="webelements">{{citeweb|url=http://webelements.com/webelements/elements/text/Uuo/key.html|title=Ununoctium|publisher=WebElements Periodic Table|accessdate=2008-01-18}}</ref> Nevertheless, researchers are highly confident that the results are not a [[false positive]], since the chance that the detections were random events was estimated to be less than one part in 100,000.<ref>{{citeweb|quote="I would say we're very confident."|url=http://pubs.acs.org/cen/news/84/i43/8443element118.html|title=Element 118 Detected, With Confidence|publisher=Chemical and Engineering news|date=2006-10-17|accessdate=2008-01-18}}</ref> In the experiments, the decay of three atoms of ununoctium was observed. A [[half-life]] of 0.89 ms was calculated: {{SimpleNuclide|Ununoctium|294}} decays into {{SimpleNuclide|Link|Ununhexium|290}} by [[alpha decay]]. Since there were only three nuclei, the halflife derived from observed lifetimes has a large uncertainty: 0.89{{±|1.07|0.31}} <!-- this appears weirdly -->ms.<ref name="full"/> : {{Nuclide|Ununoctium|294}} &rarr; {{Nuclide|Ununhexium|290}} + {{SimpleNuclide|Link|Helium}} The identification of the {{SimpleNuclide|Ununoctium|294}} nuclei was verified by separately creating the putative [[decay product|daughter nucleus]] {{SimpleNuclide|Ununhexium|290}} by means of a bombardment of {{SimpleNuclide|Link|Curium|245}} with {{SimpleNuclide|Link|Calcium|48}} ions, : {{Nuclide|Curium|245}} + {{Nuclide|Calcium|48}} &rarr; {{Nuclide|Ununhexium|290}} + 3 {{SubatomicParticle|link=yes|Neutron}} and checking that the {{SimpleNuclide|Ununhexium|290}} decay matched the [[decay chain]] of the {{SimpleNuclide|Ununoctium|294}} nuclei.<ref name="full"/> The daughter nucleus {{SimpleNuclide|Ununhexium|290}} is very unstable, decaying with a halflife of 14 milliseconds into {{SimpleNuclide|Link|Ununquadium|286}}, which may undergo [[spontaneous fission]] or alpha decay into {{SimpleNuclide|Link|Ununbium|282}}, which will undergo spontaneous fission.<ref name="full">{{citejournal|last=Oganessian|first=Yu. Ts.|coauthors=Utyonkov, V.K.; Lobanov, Yu.V.; Abdullin, F.Sh.; Polyakov, A.N.; Sagaidak, R.N.; Shirokovsky, I.V.; Tsyganov, Yu.S.; Voinov, Yu.S.; Gulbekian, G.G.; Bogomolov, S.L.; B. N. Gikal, A. N. Mezentsev, S. Iliev; Subbotin, V.G.; Sukhov, A.M.; Subotic, K; Zagrebaev, V.I.; Vostokin, G.K.; Itkis, M. G.; Moody, K.J; Patin, J.B.; Shaughnessy, D.A.; Stoyer, M.A.; Stoyer, N.J.; Wilk, P.A.; Kenneally, J.M.; Landrum, J.H.; Wild, J.H.; and Lougheed, R.W.|title=Synthesis of the isotopes of elements 118 and 116 in the {{SimpleNuclide|Californium|249}} and {{SimpleNuclide|Curium|245}} + {{SimpleNuclide|Calcium|48}} fusion reactions|journal=[[Physical Review]] C|volume=74|issue=4|pages=044602|date=2006-10-09|doi=10.1103/PhysRevC.74.044602}}</ref> In a quantum tunneling model, the alpha decay half-life of <sup>294</sup>118 was predicted to be 0.66(+0.23,-0.18)ms <ref name=half-lifes>{{citejournal|journal=Phys. Rev. C|volume=73|pages=014612|year=2006|title=α decay half-lives of new superheavy elements|author=P. Roy Chowdhury, C. Samanta, and D. N. Basu|month=January|day=26|doi=10.1103/PhysRevC.73.014612}}</ref> with the experimental Q-value published in 2004.<ref name=oga04>{{citejournal|journal=Phys. Rev. C|volume=70|pages=064609|year=2004|title=Measurements of cross sections and decay properties of the isotopes of elements 112, 114, and 116 produced in the fusion reactions 233, 238U, 242Pu, and 248Cm+48Ca |author=Yu. Ts. Oganessian et al.|doi=10.1103/PhysRevC.70.064609}}</ref> Calculation with theoretical Q-values from the macroscopic-microscopic model of Muntian-Hofman-Patyk-Sobiczewski gives somewhat low but comparable results.<ref name=npa07>{{ citejournal| journal=Nucl. Phys. A|volume=789|pages=142–154|year=2007| title=Predictions of alpha decay half lives of heavy and superheavy elements|author=C. Samanta, P. Roy Chowdhury and D.N. Basu|doi=10.1016/j.nuclphysa.2007.04.001}}</ref> Following the success in obtaining ununoctium, the discoverers have started similar experiments in the hope of creating [[element 120]] from {{SimpleNuclide|Link|Iron|58}} and {{SimpleNuclide|Link|Plutonium|244}}.<ref>{{citenews|url=https://www.llnl.gov/str/April07/pdfs/04_07.4.pdf|title=A New Block on the Periodic Table|date=April 2007|publisher=Lawrence Livermore National Laboratory|accessdate=2008-01-18}}</ref> Isotopes of the element 120 are predicted to have alpha decay half lives of the order of micro-seconds.<ref name=prc08ADNDT08>{{citejournal|journal=Phys. Rev. C|volume=77|pages=044603|year=2008|title=Search for long lived heaviest nuclei beyond the valley of stability|author=P. Roy Chowdhury, C. Samanta, and D. N. Basu|doi=10.1103/PhysRevC.77.044603}}</ref><ref>{{citejournal|journal=At. Data & Nucl. Data Tables|year=2008|title=Nuclear half-lives for α -radioactivity of elements with 100 ≤ Z ≤ 130|author=P. Roy Chowdhury, C. Samanta, and D. N. Basu|url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBB-4S26JRX-1&_user=2806701&_coverDate=03%2F14%2F2008&_alid=740505626&_rdoc=6&_fmt=high&_orig=search&_cdi=6706&_sort=d&_docanchor=&view=c&_ct=211&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=dc85a3a8a2ac1faa38c3804f16f86c13}}</ref> {{clear}} ==Naming== ''Element 118'' is still called ''[[Mendeleev's predicted elements|eka-radon]]'', but before the 1960s it was also known as ''eka-emanation'' (for the old name for radon).<ref name=60s/> Only in 1979 the [[IUPAC]] published recommendations according to which the element started to be called ''ununoctium''.<ref>{{citejournal|author=J. Chatt|journal=Pure Appl. Chem.|year=1979|volume=51|pages=381–384|title=Recommendations for the Naming of Elements of Atomic Numbers Greater than 100|doi=10.1351/pac197951020381}}</ref> The name ''ununoctium'' is a [[systematic element name]], used as a [[placeholder name|placeholder]] until it is confirmed by other research groups and the IUPAC decides on a name. Before the retraction in 2002, the researchers from Berkeley had intended to name the element ''ghiorsium (Gh)'', after [[Albert Ghiorso]] (a leading member of the research team).<ref>{{citeweb|title=Discovery of New Elements Makes Front Page News|url=http://lbl.gov/Science-Articles/Research-Review/Magazine/1999/departments/breaking_news.shtml|publisher=Berkeley Lab Research Review Summer 1999|year=1999|accessdate=2008-01-18}}</ref> Several years later, when the Russian discoverers reported their synthesis in 2006, rumors appeared that they were planning on calling it after the place of the discovery, ''dubnadium (Dn)'' (very similar to the name of [[dubnium|the 105<sup>th</sup> element, dubnium (Db)]]).<ref>{{citeweb|title= Origins of the Element Names-Names Constructed from other Words|author=D. Trapp|url=http://homepage.mac.com/dtrapp/Elements/combination2.html#116 |accessdate=2008-01-18}}</ref> Nevertheless, during an interview with a Russian newspaper, the head of the Russian institute stated the team were considering two names for the new element, ''Flyorium'' in honor of [[Georgy Flyorov]], the founder of the research institute; and ''moskovium'' (also spelled ''moscovium'' or even ''moscowium''), in recognition of the [[Moscow Oblast]] where Dubna lies.<ref>{{citeweb|url=http://news.rin.ru/eng/news/9886/9/6/|title=New chemical elements discovered in Russia`s Science City|date=2007-02-12|accessdate=2008-02-09}}</ref> He also stated that although the element was discovered as an American collaboration, who provided the californium target, the element should rightly be named in honour of Russia since the Flerov Laboratory of Nuclear Reactions at JINR is the only facility in the world which can achieve this result.<ref>{{citeweb|language=Russian|author=NewsInfo|date=2006-10-17|url=http://www.rambler.ru/news/science/0/8914394.html|title =Periodic table has expanded|publisher=Rambler|accessdate=2008-01-18|lang=ru}}</ref><ref>{{citeweb|last=Yemel'yanova|language=Russian|first=Asya |date=2006-12-17|url=http://www.vesti.ru/doc.html?id=113947|title=118th element will be named in Russian|publisher=vesti.ru|accessdate=2008-01-18|lang=ru}}</ref> ==Characteristics== ===Nucleus stability and isotopes=== [[Image:Island-of-Stability.png|thumb|250px|right|Element 118 comes right at the end of the "island of stability" and thus its nuclei are slightly more stable than predicted.]] {{seealso|Island of stability|Isotopes of ununoctium}} There are no elements with an [[atomic number]] above 82 (after [[lead]]) that have stable isotopes. The stability of nuclei decreases with the increase in atomic number, such that all isotopes with an atomic number above [[mendelevium|101]] [[radioactive decay|decay radioactive]]ly with a [[halflife]] under a day. Nevertheless, due to [[magic number (physics)|reasons]] not very well understood yet, there is a slight increased nuclear stability around elements 110–114, which leads to the appearance of what is known in nuclear physics as the "[[island of stability]]". This concept, proposed by [[UC Berkeley]] professor [[Glenn Seaborg]], explains why [[superheavy element]]s last longer than predicted.<ref>{{citebook|title=Van Nostrand's scientific encyclopedia|author=Glenn D Considine; Peter H Kulik|publisher=Wiley-Interscience|year=2002|edition=9|isbn=9780471332305}}</ref> Ununoctium is [[radioactive]] and has [[half-life]] that appears to be less than a [[millisecond]]. Nonetheless, this is still longer than some predicted values,<ref name=half-lifes>{{citejournal|journal=Phys. Rev. C|volume=73|pages=014612|year=2006|title=α decay half-lives of new superheavy elements|author=P. Roy Chowdhury, C. Samanta, and D. N. Basu|month=January|day=26|doi=10.1103/PhysRevC.73.014612}}</ref><ref>{{citejournal|title=Heaviest nuclei from 48Ca-induced reactions|author=Yuri Oganessian|year=2007|journal=J. Phys. G: Nucl. Part. Phys.|volume=34|pages=R165–R242|doi=10.1088/0954-3899/34/4/R01}}</ref> thus giving further support to the idea of this "island of stability".<ref>{{citeweb|url=http://www.dailycal.org/printable.php?id=21871|title=New Element Isolated Only Briefly|publisher=[[The Daily Californian]]|date=2006-10-18|accessdate=2008-01-18}}</ref>. Quantum tunneling model predicts existence of several neutron-rich isotopes of the element 118 with alpha decay half lives close to ms. <ref name=prc08ADNDT08>{{citejournal|journal=Phys. Rev. C|volume=77|pages=044603|year=2008|title=Search for long lived heaviest nuclei beyond the valley of stability|author=P. Roy Chowdhury, C. Samanta, and D. N. Basu|doi=10.1103/PhysRevC.77.044603}}</ref><ref>{{citejournal|journal=At. Data & Nucl. Data Tables|year=2008|title=Nuclear half-lives for α -radioactivity of elements with 100 ≤ Z ≤ 130|author=P. Roy Chowdhury, C. Samanta, and D. N. Basu|url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBB-4S26JRX-1&_user=2806701&_coverDate=03%2F14%2F2008&_alid=740505626&_rdoc=6&_fmt=high&_orig=search&_cdi=6706&_sort=d&_docanchor=&view=c&_ct=211&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=dc85a3a8a2ac1faa38c3804f16f86c13}}</ref> Theoretical calculations done on the synthetic pathways for, and the halflife of, other [[isotopes of ununoctium|isotopes]] have shown that some could be slightly more [[stable isotope|stable]] than the synthesized isotope {{SimpleNuclide|Ununoctium|294}}, most likely {{SimpleNuclide|Ununoctium|293}}, {{SimpleNuclide|Ununoctium|295}}, {{SimpleNuclide|Ununoctium|296}}, {{SimpleNuclide|Ununoctium|297}}, {{SimpleNuclide|Ununoctium|298}}, {{SimpleNuclide|Ununoctium|300}} and {{SimpleNuclide|Ununoctium|302}}.<ref name=half-lifes/><ref name=odd>{{citejournal|journal=Nuclear Physics A|volume=730|year=2004|pages=355–376|title=Entrance channels and alpha decay half-lives of the heaviest elements|author=G. Royer, K. Zbiri, C. Bonilla|doi=10.1016/j.nuclphysa.2003.11.010}}</ref> Of these, {{SimpleNuclide|Ununoctium|297}} might provide the best chances for obtaining longer-lived nuclei,<ref name=half-lifes/><ref name=odd/> and thus might become the focus of future work with this element. Some isotopes with many more neutrons, such as some located around {{SimpleNuclide|Ununoctium|313}}, could also provide longer-lived nuclei.<ref>{{citejournal|title=Half-life predictions for decay modes of superheavy nuclei|year=2004|journal=J. Phys. G: Nucl. Part. Phys.|volume=30|pages=1487–1494|doi=10.1088/0954-3899/30/10/014|author=S B Duarte, O A P Tavares, M Gonçalves, O Rodríguez, F Guzmán, T N Barbosa, F García and A Dimarco}}</ref> ===Properties=== {{seealso|Noble gas}} Ununoctium is a member of the [[inert]] gases, the zero-[[valency (chemistry)|valence]] elements. Consequently, ununoctium is expected to have similar physical and chemical properties to other members of its group, most closely resembling the noble gas above it in the periodic table, [[radon]].<ref>{{citeweb|url=http://lenntech.com/Periodic-chart-elements/Uuo-en.htm|title=Ununoctium (Uuo) - Chemical properties, Health and Environmental effects|publisher=Lenntech|accessdate=2008-01-18}}</ref> The members of this group are inert to most common chemical reactions (such as combustion, for example) because the outer [[valence shell]] is completely filled with [[octet rule|eight electrons]]. This produces a stable, minimum energy configuration in which the outer electrons are tightly bound.<ref>{{citeweb|last=Bader|first=Richard F.W.|url=http://miranda.chemistry.mcmaster.ca/esam/|title=An Introduction to the Electronic Structure of Atoms and Molecules|publisher=McMaster University|accessdate=2008-01-18}}</ref> It is thought that similarly, ununoctium has a [[closed shell|closed]] outer valence shell in which its [[valence electron]]s are arranged in a 7s<sup>2</sup>, 7p<sup>6</sup> [[electron configuration|configuration]].<ref name=Nash/> [[Image:Electron shell 118 Ununoctium.svg|thumb|200px|left|The expected [[electron shell]] diagram for ununoctium. Note the [[octet rule|eight electrons]] in the [[valence shell|outer shell]].]] Following the [[periodic trend]], ununoctium is expected to be slightly more reactive than radon; but theoretical calculations have shown that it could be quite reactive for its "noble" labeling.<ref name=Kaldor>{{citebook|title=Theoretical Chemistry and Physics of Heavy and Superheavy Elements|author=Uzi Kaldor, Stephen Wilson|pages=105|year=2003|publisher=Springer|isbn=140201371X}}</ref> In addition to being far more reactive than radon, ununoctium may be even more reactive than elements [[element 114|114]] and [[element 112|112]].<ref name=Nash>{{citejournal|title=Atomic and Molecular Properties of Elements 112, 114, and 118|author=Clinton S. Nash|journal=J. Phys. Chem. A|year=2005|volume=109|issue=15|pages=3493–3500|doi=10.1021/jp050736o}}</ref> The reason for the apparent enhancement of the chemical activity of element 118 relative to radon is an energetic destabilization and a radial expansion of the last occupied 7p [[subshell]].<ref name=Nash/><ref>the actual quote is: ''"The reason for the apparent enhancement of chemical activity of element 118 relative to radon is the energetic destabilization and radial expansion of its occupied 7p<sub>3/2</sub> [[spinor]] shell"''</ref> More precisely, considerable [[spin-orbit interaction]]s between the 7p electrons with the inert 7s<sup>2</sup> electrons, effectively lead to a second valence shell closing at [[element 114]], and a significant decrease in stabilization of the closed shell of element 118.<ref name=Nash/> It has also been calculated that ununoctium, unlike other noble gases, binds an electron with release of energy—or in other words, it exhibits positive [[electron affinity]].<ref name=Pyykko>{{citejournal|title=QED corrections to the binding energy of the eka-radon (Z=118) negative ion|author=Igor Goidenko, Leonti Labzowsky, Ephraim Eliav, Uzi Kaldor, and Pekka Pyykko¨|journal=Physical Review A|volume=67|year=2003|pages=020102(R)|doi=10.1103/PhysRevA.67.020102}}</ref><ref>{{citejournal|volume=77|issue=27|journal=Physical Review Letters|date=1996-12-30|title=Element 118: The First Rare Gas with an Electron Affinity|author=Ephraim Eliav and Uzi Kaldor|url=http://prola.aps.org/abstract/PRL/v77/i27/p5350_1|accessdate=2008-01-18}}</ref><ref>Nevertheless, [[quantum electrodynamic]] corrections have been shown to be quite significant in reducing this affinity (by decreasing the binding in the [[anion]] Uuo<sup>−</sup> by 9%) thus confirming the importance of these corrections in [[superheavy atom]]s. ''See Pyykko''</ref> Ununoctium is expected to have by far the broadest [[polarizability]] of all elements before it in the periodic table, and almost twofold of radon.<ref name=Nash/> By extrapolating this to the other noble gases, it is expected that ununoctium has a boiling point between 320 and 380 K.<ref name=Nash/> This is very different from the previously estimated values of 263 K<ref name=Seaborg>{{citebook|title=Modern Alchemy|author=Glenn Theodore Seaborg|year=1994|page=172|isbn=9810214405|publisher=World Scientific}}</ref> or 247 K.<ref>{{citejournal|journal=Journal of Radioanalytical and Nuclear Chemistry|volume=251|issue=2|year=2002|pages=299–301|title=Boiling points of the superheavy elements 117 and 118|author=N. Takahashi|doi=10.1023/A:1014880730282}}</ref> Even given the large uncertainties of the calculations, it seems highly unlikely that element 118 would be a gas under [[standard conditions]].<ref name=Nash/><ref name=note>It is debatable if the name of the group 'noble gases' will be changed if ununoctium is shown to be non-volatile.</ref> And as the liquid range of the other gases is very narrow, between 2 and 9 kelvins, this element should be [[solid]] at standard conditions. Because of its tremendous polarizability, ununoctium is expected to have an anomalously low [[ionization potential]] (similar to that of [[lead]] which is 70% of that of radon <ref name=hydride>{{citejournal|journal=Journal of Chemical Physics|volume=112|issue=6|date=2000-02-08|title=Spin–orbit effects on the transactinide p-block element monohydrides MH (M=element 113–118)|author=Young-Kyu Han, Cheolbeom Bae, Sang-Kil Son, and Yoon Sup Lee|url=http://link.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=JCPSA6000112000006002684000001|accessdate=2008-01-18}}</ref> and significantly smaller than that of element 114 <ref>{{citejournal|journal=J. Phys. Chem. A|volume=1999|issue=3|pages=402–410|title=Spin-Orbit Effects, VSEPR Theory, and the Electronic Structures of Heavy and Superheavy Group IVA Hydrides and Group VIIIA Tetrafluorides. A Partial Role Reversal for Elements 114 and 118|author=Clinton S. Nash|doi=10.1021/jp982735k|year=1999}}</ref>) and a standard state [[condensed phase]].<ref name=Nash/> Nevertheless, even if ununoctium is a [[monatomic]] [[gas]] under [[normal conditions]], it would be the highest molecular masses substance that is gaseous at standard conditions of temperature and pressure. ===Compounds and uses=== [[Image:Square-planar-3D-balls.png|right|130px|thumb|{{chem|Xe||F|4}} and {{chem|Rn||F|4}} have a square planar configuration]] [[Image:Tetrahedral-3D-balls.png|right|130px|thumb|{{chem|Uuo||F|4}} is predicted to have a tetrahedral configuration]] {{seealso|Noble gas compound}} No compounds of ununoctium have been synthesized yet, but calculations on [[theoretical chemistry|theoretical compounds]] have been performed since 1964.<ref name=60s>{{citejournal|doi=10.1016/0022-1902(65)80255-X|year=1965|publisher=Elsevier Science Ltd.|title=Some physical and chemical properties of element 118 (Eka-Em) and element 86 (Em)|author=A. V. Grosse|journal=Journal of Inorganic and Nuclear Chemistry|volume=27|issue=3|pages=509–19}}</ref> It is expected that if the [[ionization energy]] of the element is high enough, it will be difficult to [[oxidize]] and therefore, the most common [[oxidation state]] will be 0 (as for other noble gases).<ref name="compounds">{{citeweb|publisher=WebElements Periodic Table|url=http://webelements.com/webelements/elements/text/Uuo/comp.html|title=Ununoctium: Binary Compounds|accessdate=2008-01-18}}</ref> Calculations on the [[dimer]]ic [[molecule]] {{chem|Uuo|2}} showed a [[chemical bond|bonding]] interaction roughly equivalent to that calculated for [[dimercury|{{chem|Hg|2}}]], and a [[dissociation energy]] of 6 kJ/mol, roughly 4 times of that of {{chem|Rn|2}}.<ref name=Nash/> But most strikingly, it was calculated to have a [[bond length]] shorter than in {{chem|Rn|2}} by .16 Å, which would be indicative of a significant bonding interaction.<ref name=Nash/> On the other hand, the compound UuoH<sup>+</sup> exhibits a dissociation energy (in other words [[proton affinity]] of Uuo) that is smaller than that of RnH<sup>+</sup>.<ref name=Nash/> The bonding between ununoctium and [[hydrogen]] in UuoH is very weak and can be regarded as a pure [[van der Waals interaction]] rather than a true [[chemical bond]].<ref name=hydride/> On the other hand, with highly electronegative elements, ununoctium seems to form more stable compounds than for example [[element 112]] or [[element 114]].<ref name=hydride/> The stable oxidation states +2 and +4 have been predicted to exist in the [[fluor]]inated compounds {{chem|Uuo||F|2}} and {{chem|Uuo||F|4}}.<ref name=fluoride>{{citejournal|journal=J. Phys. Chem. A|volume=103|issue=8|pages=1104–1108|date=1999-02-09|title=Structures of RgFn (Rg = Xe, Rn, and Element 118. n = 2, 4.) Calculated by Two-component Spin-Orbit Methods. A Spin-Orbit Induced Isomer of (118)F<sub>4</sub>|author=Young-Kyu Han and Yoon Sup Lee|doi=10.1021/jp983665k}}</ref> This is a result of the same spin-orbit interactions that make ununoctium unusually reactive. For example, it was shown that the reaction of Uuo with {{chem|F|2}} to form the compound {{chem|Uuo||F|2}}, would release an energy of 106 kcal/mol of which about 46 kcal/mol come from these interactions.<ref name=hydride/> For comparison, the spin-orbit interaction for the similar molecule {{chem|Rn||F|2}} is about 10 kcal/mol out of a formation energy of 49 kcal/mol.<ref name=hydride/> The same interaction stabilizes the [[tetrahedral molecular geometry|tetrahedral T<sub>d</sub> configuration]] for {{chem|Uuo||F|4}}, as opposed to the [[square planar|square planar D<sub>4h</sub> one]] of [[xenon tetrafluoride|{{chem|Xe||F|4}}]] and {{chem|Rn||F|4}}.<ref name=fluoride/> The Uuo-F bond will most probably be [[ionic bond|ionic]] rather than [[covalent bond|covalent]], rendering the {{chem|Uuo||F|n}} compounds non-volatile.<ref name=Kaldor/><ref>{{citejournal|journal=J. Chem. Soc., Chem. Commun.|year=1975|pages=760b–761|doi=10.1039/C3975000760b|title=Fluorides of radon and element 118|author=Kenneth S. Pitzer}}</ref> Unlike the other noble gases, ununoctium was predicted to be sufficiently [[electropositive]] to form a Uuo-Cl bond with [[chlorine]].<ref name=Kaldor/> Since only three atoms of ununoctium have ever been produced, it currently has no uses outside of basic scientific research. It would constitute a [[radiation poisoning|radiation hazard]] if enough were ever assembled in one place.<ref name=70s>{{citeweb|publisher=WebElements Periodic Table|url=http://webelements.com/webelements/elements/text/Uuo/biol.html|title=Ununoctium: Biological information|accessdate=2008-01-18}}</ref> ==References== {{reflist|2}} ==See also== {{wikinews|Controversy-Plagued Element 118, the Heaviest Atom Yet, Finally Discovered}} {{Commons|Ununoctium}} *[[Transuranic element]] *[[Ununhexium]] ==External links== *[http://web.archive.org/web/20061129112314/http://flerovlab.jinr.ru/flnr/elm118.html ELEMENT 118: EXPERIMENTS on DISCOVERY], archive of discoverers' official web page *[http://www.chemistry-blog.com/2006/10/16/discovery-of-element-118-by-oganessian-dont-call-it-ununoctium/ Chemistry-Blog: Independent analysis of 118 claim] *[http://webelements.com/ununoctium/ WebElements: Ununoctium] *[http://www.apsidium.com/elements/118.htm Apsidium: Ununoctium - Moskowium] *[http://education.jlab.org/itselemental/ele118.html It's Elemental: Ununoctium] *[http://iupac.org/publications/pac/75/10/1601/ On the Claims for Discovery of Elements 110, 111, 112, 114, 116, and 118 (IUPAC Technical Report)] <!-- http://den-za-dnem.ru/page.php?article=319 http://inopressa.ru/nytimes/2006/10/17/12:17:55/element --> {{Compact periodic table}} {{featured article}} [[Category:Chemical elements]] [[Category:Noble gases]] [[Category:Synthetic elements]] [[Category:Nuclear physics]] [[af:Ununoctium]] [[als:Ununoctium]] [[ar:أنون أوكتيوم]] [[ast:Ununoctiu]] [[bn:ইউনুনোকটিয়াম]] [[be:Унуноктый]] [[bs:Ununoktijum]] [[ca:Ununocti]] [[cs:Ununoctium]] [[co:Ununoctiu]] [[da:Ununoctium]] [[de:Ununoctium]] [[et:Ununoktium]] [[el:Ununoctium]] [[es:Ununoctio]] [[eo:Ununoktio]] [[eu:Ununoktio]] [[fr:Ununoctium]] [[fur:Ununoctium]] [[ga:Únúnoictiam]] [[gv:Oonoonoctium]] [[gl:Ununoctio]] [[ko:우누녹튬]] [[hr:Ununoktij]] [[id:Ununoktium]] [[it:Ununoctio]] [[he:אונונאוקטיום]] [[la:Ununoctium]] [[lb:Ununoctium]] [[hu:Ununoctium]] [[ml:അണ്‍അണ്‍ഒക്റ്റിയം]] [[nl:Ununoctium]] [[ja:ウンウンオクチウム]] [[no:Ununoctium]] [[nn:Ununoctium]] [[nds:Ununoctium]] [[pl:Ununoctium]] [[pt:Ununóctio]] [[ro:Ununoctiu]] [[ru:Унуноктий]] [[scn:Ununoctiu]] [[sk:Ununoctium]] [[sl:Ununoktij]] [[sr:Унуноктијум]] [[sh:Ununoktijum]] [[fi:Ununoktium]] [[sv:Ununoctium]] [[th:อูนอูนออกเทียม]] [[vi:Ununocti]] [[tr:Ununoktiyum]] [[uk:Унуноктій]] [[zh:Uuo]]