Editing Extended periodic table (section)

===Searches in nature===
A study in 1976 by a group of American researchers from several universities proposed that [[primordial element|primordial]] superheavy elements, mainly [[livermorium]], elements 124, 126, and 127, could be a cause of unexplained radiation damage (particularly [[radiohalos]]) in minerals.<ref name=Transuraniumppl/> This prompted many researchers to search for them in nature from 1976 to 1983. A group led by Tom Cahill<!--don't link, this Tom Cahill does not have an article-->, a professor at the [[University of California, Davis|University of California at Davis]], claimed in 1976 that they had detected [[alpha particle]]s and [[X-ray]]s with the right energies to cause the damage observed, supporting the presence of these elements. In particular, the presence of long-lived (on the order of 10<sup>9</sup> years) nuclei of elements 124 and 126, along with their decay products, at an abundance of 10<sup>−11</sup> relative to their possible [[congener (chemistry)|congeners]] [[uranium]] and [[plutonium]], was conjectured.<ref name=symposium>{{cite book |editor1-last=Lodhi |editor1-first=M.A.K. |title=Superheavy Elements: Proceedings of the International Symposium on Superheavy Elements |location= Lubbock, Texas |publisher=Pergamon Press |date=March 1978 |isbn=978-0-08-022946-1}}</ref> Others claimed that none had been detected, and questioned the proposed characteristics of primordial superheavy nuclei.<ref name=Transuraniumppl/> In particular, they cited that any such superheavy nuclei must have a closed neutron shell at ''N''&nbsp;=&nbsp;184 or ''N''&nbsp;=&nbsp;228, and this necessary condition for enhanced stability only exists in neutron deficient isotopes of livermorium or neutron rich isotopes of the other elements that would not be [[beta-decay stable isobars|beta-stable]]<ref name=Transuraniumppl/> unlike most naturally occurring isotopes.<ref name=nubase>{{cite journal|last1=Audi|first1=G.|last2=Kondev|first2=F.G.|last3=Wang|first3=M.|last4=Huang|first4=W.J.| last5=Naimi|first5=S.|title=The NUBASE2016 evaluation of nuclear properties|url=http://amdc.in2p3.fr/nubase/2017Audi03.pdf|journal=Chinese Physics C|volume=41|issue=3|date=2017|pages=030001|doi=10.1088/1674-1137/41/3/030001|bibcode=2017ChPhC..41c0001A}}</ref> This activity was also proposed to be caused by nuclear transmutations in natural [[cerium]], raising further ambiguity upon this claimed observation of superheavy elements.<ref name=Transuraniumppl/>

On April 24, 2008, a group led by [[Amnon Marinov]] at the [[Hebrew University of Jerusalem]] claimed to have found single atoms of <sup>292</sup>122 in naturally occurring [[thorium]] deposits at an abundance of between 10<sup>−11</sup> and 10<sup>−12</sup> relative to thorium.<ref name=arxiv/> The claim of Marinov et al. was criticized by a part of the scientific community. Marinov claimed that he had submitted the article to the journals ''[[Nature (journal)|Nature]]'' and ''[[Nature Physics]]'' but both turned it down without sending it for peer review.<ref>[[Royal Society of Chemistry]], "[http://rsc.org/chemistryworld/News/2008/May/02050802.asp Heaviest element claim criticised] {{Webarchive|url=https://web.archive.org/web/20160304042449/http://rsc.org/chemistryworld/News/2008/May/02050802.asp |date=2016-03-04 }}", Chemical World.</ref> The <sup>292</sup>122 atoms were claimed to be [[superdeformation|superdeformed]] or [[hyperdeformation|hyperdeformed]] [[nuclear isomer|isomers]], with a half-life of at least 100 million years.<ref name="emsley"/>

A criticism of the technique, previously used in purportedly identifying lighter [[thorium]] isotopes by [[mass spectrometry]],<ref name="thorium">{{cite journal |journal=Phys. Rev. C |title=Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes |year=2007 |volume=76 |page=021303(R) |doi=10.1103/PhysRevC.76.021303 |first1=A. |last1=Marinov |first2=I. |last2=Rodushkin |first3=Y. |last3=Kashiv |first4=L. |last4=Halicz |first5=I. |last5=Segal |first6=A. |last6=Pape |first7=R. V. |last7=Gentry |first8=H. W. |last8=Miller |first9= D. |last9=Kolb |first10=R. |last10=Brandt |arxiv = nucl-ex/0605008 |bibcode = 2007PhRvC..76b1303M |issue=2 |s2cid=119443571 }}</ref> was published in ''[[Physical Review C]]'' in 2008.<ref>{{cite journal |journal=Phys. Rev. C |title=Comment on 'Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes' |year=2009 |volume=79 |pages=049801 |doi=10.1103/PhysRevC.79.049801 |author1=R. C. Barber |author2=J. R. De Laeter |bibcode = 2009PhRvC..79d9801B |issue=4 }}</ref> A rebuttal by the Marinov group was published in ''Physical Review C'' after the published comment.<ref>{{cite journal |journal=Phys. Rev. C |title=Reply to "Comment on 'Existence of long-lived isomeric states in naturally-occurring neutron-deficient Th isotopes'" |year=2009 |volume=79 |pages=049802 |doi=10.1103/PhysRevC.79.049802 |author1=A. Marinov |author2=I. Rodushkin |author3=Y. Kashiv |author4=L. Halicz |author5=I. Segal |author6=A. Pape |author7=R. V. Gentry |author8=H. W. Miller |author9=D. Kolb |author10=R. Brandt |bibcode = 2009PhRvC..79d9802M |issue=4 }}</ref>

A repeat of the thorium experiment using the superior method of [[Accelerator mass spectrometry|Accelerator Mass Spectrometry]] (AMS) failed to confirm the results, despite a 100-fold better sensitivity.<ref>{{cite journal |journal=Phys. Rev. C |title=Search for long-lived isomeric states in neutron-deficient thorium isotopes |year=2008 |volume=78 |page= 064313 |doi=10.1103/PhysRevC.78.064313 |author1=J. Lachner |author2=I. Dillmann |author3=T. Faestermann |author4=G. Korschinek |author5=M. Poutivtsev |author6=G. Rugel |bibcode = 2008PhRvC..78f4313L |issue=6 |arxiv = 0907.0126 |s2cid=118655846 }}</ref> This result throws considerable doubt on the results of the Marinov collaboration with regard to their claims of long-lived isotopes of [[thorium]],<ref name="thorium"/> [[roentgenium]]<ref name="roentgenium">{{cite journal |last1=Marinov |first1=A. |last2=Rodushkin |first2=I. |last3=Pape |first3=A. |last4=Kashiv |first4=Y. |last5=Kolb |first5=D. |last6=Brandt |first6=R. |last7=Gentry |first7=R. V. |last8=Miller |first8=H. W. |last9=Halicz |first9=L. |first10=I. |last10=Segal |year=2009 |title=Existence of Long-Lived Isotopes of a Superheavy Element in Natural Au |journal=[[International Journal of Modern Physics E]] |volume=18 |number=3 |pages=621–629 |doi=10.1142/S021830130901280X |url=http://www.phys.huji.ac.il/~marinov/publications/Au_paper_IJMPE_73.pdf |access-date=February 12, 2012 |arxiv=nucl-ex/0702051 |bibcode=2009IJMPE..18..621M |s2cid=119103410 |url-status=dead |archiveurl=https://web.archive.org/web/20140714210340/http://www.phys.huji.ac.il/~marinov/publications/Au_paper_IJMPE_73.pdf |archive-date=July 14, 2014 }}</ref> and element 122.<ref name=arxiv>{{cite journal |last=Marinov |first=A. |author2=Rodushkin, I. |author3=Kolb, D. |author4=Pape, A. |author5=Kashiv, Y. |author6=Brandt, R. |author7=Gentry, R. V. |author8= Miller, H. W. |title=Evidence for a long-lived superheavy nucleus with atomic mass number A=292 and atomic number Z=~122 in natural Th |journal= International Journal of Modern Physics E|year=2010 |arxiv=0804.3869 |bibcode = 2010IJMPE..19..131M |doi = 10.1142/S0218301310014662 |volume=19 |issue=1 |pages=131–140 |s2cid=117956340 }}</ref> It is still possible that traces of unbibium might only exist in some thorium samples, although this is unlikely.<ref name="emsley"/>

The possible extent of primordial superheavy elements on Earth today is uncertain. Even if they are confirmed to have caused the radiation damage long ago, they might now have decayed to mere traces, or even be completely gone.<ref name="emsley2">{{cite book|last=Emsley|first=John|title=Nature's Building Blocks: An A–Z Guide to the Elements |edition=New |year=2011 |publisher=Oxford University Press|location=New York |isbn=978-0-19-960563-7|page=592}}</ref> It is also uncertain if such superheavy nuclei may be produced naturally at all, as [[spontaneous fission]] is expected to terminate the [[r-process]] responsible for heavy element formation between mass number 270 and 290, well before elements beyond 120 may be formed.<ref>{{cite journal|last1=Petermann |first1=I|last2=Langanke|first2=K.|last3=Martínez-Pinedo|first3=G.|last4=Panov|first4=I.V |last5=Reinhard|first5=P.G.|last6=Thielemann|first6=F.K.|date=2012|title=Have superheavy elements been produced in nature?|journal=European Physical Journal A|volume=48|issue=122|page=122|url=https://www.researchgate.net/publication/229156774|doi=10.1140/epja/i2012-12122-6|arxiv=1207.3432|bibcode=2012EPJA...48..122P|s2cid=119264543}}</ref>

A recent hypothesis tries to explain the spectrum of [[Przybylski's Star]] by naturally occurring [[flerovium]] and element 120.<ref name=Isotope1>{{cite web|url=https://sites.psu.edu/astrowright/2017/03/16/przybylskis-star-iii-neutron-stars-unbinilium-and-aliens/|title=Przybylski's Star III: Neutron Stars, Unbinilium, and aliens|author=Jason Wright|date=16 March 2017|access-date=31 July 2018}}</ref><ref name=Isotope2>{{Cite journal|title=Isotope shift and search for metastable superheavy elements in astrophysical data|journal = Physical Review A|volume = 95|issue = 6|pages = 062515|author1=V. A. Dzuba|author2=V. V. Flambaum|author3=J. K. Webb|arxiv=1703.04250|doi = 10.1103/PhysRevA.95.062515|year = 2017|bibcode=2017PhRvA..95f2515D|s2cid = 118956691}}</ref><ref name=SciShowSpace>Archived at [https://ghostarchive.org/varchive/youtube/20211211/XKD0pFYewu4 Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20190605060157/https://www.youtube.com/watch?v=XKD0pFYewu4 Wayback Machine]{{cbignore}}: {{cite web|url=https://www.youtube.com/watch?v=XKD0pFYewu4|title=This Star Might Be Hiding Undiscovered Elements. Przybylski's Star|author=SciShow Space|website=youtube.com|date=31 July 2018|access-date=31 July 2018}}{{cbignore}}</ref>