Island of stability 66394 225875902 2008-07-15T20:33:14Z JMTCP 6770253 Changed: "as yet (2009)" to "as yet (2008)" It is still 2008, not 2009. [[Image:Island-of-Stability.png|thumb|500px|right|3-dimensional rendering of the theoretical Island of Stability.]] The '''island of stability''' is a term from [[nuclear physics]] that describes the possibility of [[chemical element|element]]s with particularly stable "[[Magic number (physics)|magic numbers]]" of [[proton]]s and [[neutron]]s. This would allow certain [[isotope]]s of some [[transuranic element]]s to be far more stable than others; that is, [[radioactive decay|decay]] much more slowly. __TOC__ The idea of the island of stability was first proposed by [[Glenn T. Seaborg]]. The [[hypothesis]] is that the [[atomic nucleus]] is built up in "shells" in a manner similar to the electron shells in atoms. In both cases shells are just groups of quantum [[energy level]]s that are relatively close to each other. Energy levels from quantum states in two different shells will be separated by a relatively large energy gap. So when the number of [[neutron]]s and [[proton]]s completely fill the [[energy level]]s of a given shell in the nucleus, the [[binding energy]] per nucleon will reach a local minimum and thus that particular configuration will have a longer lifetime than nearby isotopes that do not have filled shells.<ref>{{cite web | title = Shell Model of Nucleus | work = HyperPhysics | publisher = Department of Physics and Astronomy, Georgia State University | url = http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/shell.html | accessdate = 2007-01-22 }}</ref> A filled shell would have "[[Magic number (physics)|magic numbers]]" of neutrons and protons. One possible magic number of neutrons is 184, and some possible matching proton numbers are 114, 120 and 126 &mdash; which would mean that the most stable possible isotopes would be [[ununquadium]]-298, [[unbinilium]]-304 and [[unbihexium]]-310. Of particular note is Ubh-310, which would be "[[Magic number (physics)#Doubly magic|doubly magic]]" (both its proton number of 126 and neutron number of 184 are thought to be magic) and thus the most likely to have a very long half-life. (The next lighter doubly-magic nucleus is [[Lead]]-208, the heaviest stable nucleus and most stable heavy metal.) None of these transuranic isotopes has yet been produced, but isotopes of elements in the range between 110 through 114 are slower to decay than isotopes of nearby nuclei on the [[periodic table]]. ==Half-lives of large isotopes== [[Image:Periodic Table by Radioactivity.PNG|right|450px|thumb|Periodic table colored according to the half-life of their most stable isotope .<br> (1) <span style="color:blue">stable elements.</span><br> (2) <span style="color:green">radioactive elements with isotopes with very long decay half-times.</span> Their half-live of over a million years gives them very small, if not negligible radioactivities and thus may be handled without any precautions.</span><br> (3) <span style="color:#FFD800">radioactive elements that may present low health hazards.</span> Their half-time of over 500 years allows them to have commercial applications due to the fact that their radiation levels are near the [[background radiation|background one]].<br> (4) <span style="color:#FF7E00">radioactive elements that are known to pose high safety risks.</span> Their half-life of over a day and their radioactivity levels make them have little potential for any commercial use.<br> (5) <span style="color:red">highly radioactive elements.</span> Because of their half-time as low as a couple of minutes, they pose severe health risks and is unlikely that they will receive any use outside basic research.</span><br> (6) <span style="color:brown">extremely radioactive elements.</span> Very little is known about these elements, and will likely never receive any attention outside research laboratories.</span>]] [[Fermium]] is the largest element that can be produced in a [[nuclear reactor]]. The stability (half-life of the longest-lived isotope) of elements generally decreases from element&nbsp;101 to element&nbsp;109 and then approaches an island of stability with longer-lived isotopes in the range of elements&nbsp;111 and 114<ref name="Emsley"> {{cite book | last = Emsley | first = John | title = Nature's Building Blocks | edition = (Hardcover, First Edition) | publisher = [[Oxford University Press]] | date = 2001 | pages = (pages 143,144,458) | id = ISBN 0198503407 }}</ref>. The longest-lived observed isotopes are shown in the following table. {| class="wikitable sortable" |+ Isotopes of elements 100 through 118<ref name="Emsley" /> ! Number !! Name !! Longest-lived <br> isotope !! Half-life of <br> longest-lived isotope !! Link |- ! 100 | [[fermium]] || <sup>257</sup>Fm || 101 days || [[Isotopes of fermium]] |- ! 101 | [[mendelevium]] || <sup>258</sup>Md || 52 days || [[Isotopes of mendelevium]] |- ! 102 | [[nobelium]] || <sup>259</sup>No || 58 minutes || [[Isotopes of nobelium]] |- ! 103 | [[lawrencium]] || <sup>262</sup>Lr || 3.6 hours || [[Isotopes of lawrencium]] |- ! 104 | [[rutherfordium]] || <sup>267</sup>Rf || 1.3 hours|| [[Isotopes of rutherfordium]] |- ! 105 | [[dubnium]] || <sup>268</sup>Db || 29 hours|| [[Isotopes of dubnium]] |- ! 106 | [[seaborgium]] || <sup>271</sup>Sg || 1.9 minutes || [[Isotopes of seaborgium]] |- ! 107 | [[bohrium]] || <sup>270</sup>Bh || 61 seconds || [[Isotopes of bohrium]] |- ! 108 | [[hassium]] || <sup>277</sup>Hs || 16.5 minutes || [[Isotopes of hassium]] |- ! 109 | [[meitnerium]] || <sup>278</sup>Mt || 0.72 seconds || [[Isotopes of meitnerium]] |- ! 110 | [[darmstadtium]] || <sup>281</sup>Ds|| 11 seconds || [[Isotopes of darmstadtium]] |- ! 111 | [[roentgenium]] || <sup>280</sup>Rg || 3.6 seconds || [[Isotopes of roentgenium]] |- ! 112 | [[ununbium]] || <sup>285</sup>Uub || 29 seconds || [[Isotopes of ununbium]] |- ! 113 | [[ununtrium]] || <sup>284</sup>Uut || 0.49 seconds || [[Isotopes of ununtrium]] |- ! 114 | [[ununquadium]] || <sup>289</sup>Uuq || 2.6 seconds || [[Isotopes of ununquadium]] |- ! 115 | [[ununpentium]] || <sup>288</sup>Uup || 88 ms || [[Isotopes of ununpentium]] |- ! 116 | [[ununhexium]] || <sup>293</sup>Uuh || 61 ms || [[Isotopes of ununhexium]] |- ! 117 | [[ununseptium]] || Yet unknown || N/A || [[Isotopes of ununseptium]] |- ! 118 | [[ununoctium]] || <sup>294</sup>Uuo || 0.89 ms || [[Isotopes of ununoctium]] |- |} The [[half-life|half lives]] of elements in the island are uncertain. Many physicists think they are relatively short, on the order of minutes, hours, or perhaps days. However, some theoretical calculations indicate that their half lives may be long (some calculations put it on the order of 10<sup>9</sup> years)<ref>[http://ie.lbl.gov/toipdf/theory.pdf Moller Theoretical Nuclear Chart 1997]</ref>. It is possible that these elements could have unusual chemical properties, and, if long lived enough, various applications (such as targets in nuclear physics and [[neutron source]]s). However, the isotopes of several of these elements still have too few neutrons to be stable. The island of stability still hasn't been reached, since the island's "shores" have neutron richer nuclides than those produced. The alpha-decay half-lives of 1700 nuclei with 100 ≤ Z ≤ 130 have been calculated in a quantum tunneling model with both experimental and theoretical alpha-decay Q-values. <ref name=half-lifesall>{{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|url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000073000001014612000001&idtype=cvips&gifs=yes|doi=10.1103/PhysRevC.73.014612}}</ref><ref>{{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|url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVB-4NF4F0Y-2&_user=2806701&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=3f680654b5659191d67f31681a4cfc83| doi=10.1016/j.nuclphysa.2007.04.001}}</ref><ref>{{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|url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000077000004044603000001&idtype=cvips&gifs=yes|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><ref>{{citejournal|journal=Phys. Rev. C|volume=75|pages= 047306|year=2007|title=α decay chains from element 113|author=P. Roy Chowdhury, D. N. Basu and C. Samanta |month=January|day=26|url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000075000004047306000001&idtype=cvips&gifs=yes|doi=10.1103/PhysRevC.75.047306}}</ref><ref>{{cite journal | doi = 10.1143/JPSJ.76.124201 | title = Quantum tunneling in <sup>277</sup>112 and its alpha-decay chain | author = Chhanda Samanta, Devasish Narayan Basu, and Partha Roy Chowdhury | journal = [[Journal of the Physical Society of Japan]] | year = 2007 | volume = 76 | pages = 124201–124204}}</ref> The theoretical calculations are in good agreement with the available experimental data. ==Island of relative stability== <sup>232</sup>Th ([[thorium]]), <sup>235</sup>U and <sup>238</sup>U ([[uranium]]) are the only naturally occurring isotopes beyond [[bismuth]] that are relatively stable over the current lifespan of the universe. Bismuth was found to be unstable in 2003, with an [[Alpha particle|α]]-emission half-life of 1.9 × 10<sup>19</sup> years for [[Bismuth-209|Bi-209]]. All other isotopes beyond bismuth are relatively or very unstable. So the main periodic table ends at bismuth, with an island at thorium and uranium. Between bismuth and thorium there is a sea trough of severe instability, which renders such elements as [[astatine]], [[radon]], and [[francium]] extremely short-lived relative to all but the heaviest elements found so far. Current theoretical investigation indicates that in the region Z =106-108 and N~160-164 a small ‘island/peninsula’ might survive fission and beta-decay, and superheavy nuclei in this region might predominantly undergo alpha decay.<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|url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVB-4NF4F0Y-2&_user=2806701&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=3f680654b5659191d67f31681a4cfc83| doi=10.1016/j.nuclphysa.2007.04.001}}</ref><ref>{{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|url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000077000004044603000001&idtype=cvips&gifs=yes|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>. Also, <sup>298</sup>114 is not the center of the magic island as predicted earlier. <ref name=Nilsson1969>{{citejournal|journal=Nucl. Phys. A Tables|year=1969|title=On the nuclear structure and stability of heavy and superheavy elements |author=Sven Gösta Nilsson, Chin Fu Tsang, Adam Sobiczewski, Zdzislaw Szymaski and, Slawomir Wycech, Christer Gustafson, Inger-Lena Lamm, Peter Möller and, Björn Nilsson|url= http://www.sciencedirect.com/science?_ob=ArticleListURL&_method=list&_ArticleListID=745546610&_sort=d&view=c&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=325c9fc8ab851444ddd2450f32585b97}}</ref> On the contrary, the nucleus with Z=110, N=183 appears to be near the center of a possible 'magic island' (Z=104 -116, N~176 -186). In the N~162 region the beta-stable, fission survived <sup>268</sup>106 is predicted to have alpha-decay half life ~3.2hrs that is greater than that (~28s) of the deformed doubly-magic <sup>270</sup>108.<ref name=Dvorak>{{citejournal|journal=Phys. Rev. Lett. |volume=97|pages= 242501|year=2006|title=Doubly Magic Nucleus <sup>270</sup>108 Hs-162|author= J. Dvorak, W. Brüchle, M. Chelnokov, R. Dressler, Ch. E. Düllmann, K. Eberhardt, V. Gorshkov, E. Jäger, R. Krücken, A. Kuznetsov, Y. Nagame, F. Nebel,1 Z. Novackova, Z. Qin, M. Schädel, B. Schausten, E. Schimpf, A. Semchenkov, P. Thörle, A. Türler, M. Wegrzecki, B. Wierczinski, A. Yakushev, and A. Yeremin|url= http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRLTAO000097000024242501000001&idtype=cvips&gifs=yes|doi=10.1103/PhysRevLett.97.242501}}</ref> The superheavy nuclei <sup>268</sup>106 has not been produced in the laboratory as yet (2008). For superheavy nuclei with Z >116 and N ~184 the alpha-decay half-lives are predicted to be less than one second. The Z=120, 124, 126 with N=184 are predicted to form spherical doubly-magic nuclei and survive fission.<ref name=Cwiok>{{citejournal|journal=Nature |volume=433|pages= 705|year=2005|title= Shape coexistence and triaxiality in the superheavy nuclei|author= S. Cwiok, P.-H. Heenen and W. Nazarewicz |url=http://www.phys.utk.edu/witek/fission/utk/Papers/natureSHE.pdf|doi= 10.1038/nature03336 }}</ref> Calculations in a quantum tunneling model show that such superheavy nuclei would undergo alpha-decay within microseconds or, less. <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|url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVB-4NF4F0Y-2&_user=2806701&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=3f680654b5659191d67f31681a4cfc83| doi=10.1016/j.nuclphysa.2007.04.001}}</ref><ref>{{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|url=http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRVCAN000077000004044603000001&idtype=cvips&gifs=yes|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>. ==Synthesis problems== {{Unreferencedsection|date=July 2008}} Manufacturing nuclei in the island of stability may be very difficult, because the nuclei available would not deliver the necessary sum of neutrons. So for the synthesis of isotope 298 of [[Ununquadium|element 114]] by using plutonium and calcium, one would require an isotope of plutonium and one of calcium, which have together a sum of at least 298 nucleons (more is better, because at the nuclei reaction some neutrons are emitted). This would require for example in the case of synthesis of element 114 the usage of calcium-50 and plutonium-248. However these isotopes (and heavier calcium and plutonium isotopes) are not available in weighable quantities. This is also the fact for other target/projectile-combinations. However it may be possible to generate the isotope 298 of element 114, if nuclear transfer reactions would work. One of these reactions may be: :<sup>204</sup>Hg + <sup>136</sup>Xe → <sup>298</sup>Uuq + <sup>40</sup>Ca + 2n ==References== {{Reflist}} ==See also== * Island of stability: [[Ununquadium]] — [[Unbinilium]] — [[Unbihexium]] * [[Table of nuclides (combined)|Table of nuclides]] — a visualization of the island of stability * [[Periodic table]] and [[Periodic table (extended)]] * [[Douglas Preston]] and [[Lincoln Child]] featured the island of stability in their 2000 novel ''[[The Ice Limit]]''. ==External links== * [http://arxivblog.com/?p=350 The hunt for superheavy elements] (April 7, 2008) * [http://159.93.28.88/popeko/e114_287.html The synthesis of spherical superheavy nuclei in 48Ca induced reactions] (needs login so can not access !) * [http://www.radiochemistry.org/periodictable/elements/115.html Uut and Uup Add Their Atomic Mass to Periodic Table] (Feb 2004) * [http://www.ias.ac.in/currsci/aug10/articles9.htm New elements discovered and the island of stability sighted] (Aug 1999 - includes report on article later retracted) * [http://www.cerncourier.com/main/article/39/7/18 First postcard from the island of nuclear stability] (1999) * [http://www.cerncourier.com/main/article/41/8/17 Second postcard from the island of stability] (Oct 2001) * [http://imglib.lbl.gov/ImgLib/COLLECTIONS/BERKELEY-LAB/SEABORG-ARCHIVE/index/96B05658.html Superheavy Elements "Island of Stability"] (single text slide - undated) * [http://physicsweb.org/articles/world/17/7/7 Superheavy elements] (Jul 2004 Yuri Oganessian of JINR ) * [http://curious.astro.cornell.edu/question.php?number=599 Can superheavy elements (such as Z=116 or 118) be formed in a supernova? Can we observe them?] * [http://www.pbs.org/wgbh/nova/sciencenow/3313/02.html NOVA - Island of Stability] <!-- Ninov fraud not to be used: * http://www.lbl.gov/Science-Articles/Archive/elements-116-118.html --> * [http://www.nytimes.com/2004/02/08/opinion/08SACK.html?ex=1391576400&en=68476e9da837f91f&ei=5007&partner=USERLAND New York Times Editorial by Oliver Sacks regarding the Island of Stability theory] (Feb 2004 re 113 and 115) [[Category:Chemical elements|*]] [[Category:Isotopes]] [[Category:Periodic table]] [[Category:Radioactivity]] [[ar:جزيرة ثبات]] [[de:Insel der Stabilität]] [[es:Isla de estabilidad]] [[fr:Îlot de stabilité]] [[ko:안정성의 섬]] [[pl:Wyspa stabilności]] [[ru:Остров стабильности]] [[sk:Ostrov stability]] [[fi:Stabiilisuuden saari]] [[zh:稳定岛]]