Editing Hassium (section)

== Natural occurrence ==

[[File:Molybdenit 1.jpg|thumb|upright=1.00|alt=Dark reflective crystal of molybdenite|[[Molybdenite]]|right]]

Hassium is not known to occur naturally on Earth; all its known isotopes are so [[half-life|short-lived]] that no [[primordial element|primordial]] hassium would survive to today. This does not rule out the possibility of unknown, longer-lived isotopes or [[nuclear isomer]]s, some of which could still exist in [[trace radioisotope|trace]] quantities if they are long-lived enough. As early as 1914, German physicist [[Richard Swinne]] proposed element{{spaces}}108 as a source of [[X-rays]] in the [[Greenland ice sheet]]. Though Swinne was unable to verify this observation and thus did not claim discovery, he proposed in 1931 the existence of "regions" of long-lived transuranic elements, including one around ''Z''{{spaces}}={{spaces}}108.{{sfn|Kragh|2018|pages=9–10}}

In 1963, Soviet geologist and physicist Viktor Cherdyntsev, who had previously claimed the existence of primordial [[curium]]-247,<ref>{{cite journal |last1=Cherdyntsev |first1=V. V. |last2=Mikhailov |first2=V. F. |date=1963 |title=Первозданный заурановый изотоп в природе |trans-title=The Primordial Transuranium Isotope in Nature |journal=Geokhimiya |volume=1 |pages=3–14 |osti=4748393 |language=ru}}</ref> claimed to have discovered element{{spaces}}108—specifically the {{sup|267}}108 isotope, which supposedly had a half-life of 400 to 500{{spaces}}million years—in natural [[molybdenite]] and suggested the provisional name ''sergenium'' (symbol Sg);<ref name="Nikitin" />{{efn|At the time, this symbol had not yet been taken by seaborgium.}} this name comes from the name for the [[Silk Road]] and was explained as "coming from [[Kazakh Soviet Socialist Republic|Kazakhstan]]" for it.<ref name="Nikitin">{{Cite journal|last=Nikitin|first=A.|date=1970|title=Новый трансуран найден в природе|trans-title=New transuranium found in nature|journal=[[Nauka i Zhizn]]|language=ru|volume=2|pages=102–106}}</ref> His rationale for claiming that sergenium was the heavier homologue to osmium was that minerals supposedly containing sergenium formed [[Volatility (chemistry)|volatile]] oxides when boiled in [[nitric acid]], similarly to osmium.<ref name="Kulakov" />

Soviet physicist Vladimir Kulakov criticized Cherdyntsev's findings on the grounds that some of the properties Cherdyntsev claimed sergenium had, were inconsistent with then-current nuclear physics. The chief questions Kulakov raised were that the claimed alpha decay energy of sergenium was many orders of magnitude lower than expected and the half-life given was eight orders of magnitude shorter than what would be predicted for a nuclide alpha-decaying with the claimed decay energy. At the same time, a corrected half-life in the region of 10{{sup|16}}{{spaces}}years would be impossible because it would imply the samples contained ~100 milligrams of sergenium.<ref name="Kulakov">{{cite journal|last1=Kulakov|first1=V. M.|date=1970|title=Has element 108 been discovered?|journal=Soviet Atomic Energy|volume=29|issue=5 |pages=1166–1168|doi=10.1007/BF01666716|s2cid=95772762}}</ref> In 2003, it was suggested that the observed alpha decay with energy 4.5{{spaces}}[[electronvolt|MeV]] could be due to a low-energy and strongly enhanced transition between different [[hyperdeformation|hyperdeformed]] states of a hassium isotope around {{sup|271}}Hs, thus suggesting that the existence of superheavy elements in nature was at least possible, but unlikely.<ref>{{cite journal |last1=Marinov |first1=A. |author-link=Amnon Marinov |last2=Gelberg |first2=S. |last3=Kolb |first3=D. |last4=Brandt |first4=R. |last5=Pape |first5=A. |display-authors=3 |title=New outlook on the possible existence of superheavy elements in nature |journal=Physics of Atomic Nuclei |volume=66 |issue=6 |pages=1137–1145 |doi=10.1134/1.1586428 |arxiv = nucl-ex/0210039 |bibcode = 2003PAN....66.1137M |year=2003|s2cid=119524738}}</ref>

In 2006, Russian geologist Alexei Ivanov hypothesized that an isomer of {{sup|271}}Hs might have a half-life of ~{{val|2.5e8|0.5}} years, which would explain the observation of alpha particles with energies of ~4.4{{spaces}}MeV in some samples of molybdenite and [[osmiridium]].<ref name="natural" /> This isomer of {{sup|271}}Hs could be produced from the [[beta decay]] of {{sup|271}}Bh and {{sup|271}}Sg, which, being homologous to [[rhenium]] and molybdenum<!--don't change it to tungsten. The point is that Hs is being predicted to occur in molybdenite, which has Mo and some Re in it. W is speculation not supported by the source. This is ALREADY a speculation so we should be cautious.--> respectively, should occur in molybdenite along with rhenium and molybdenum if they occurred in nature. Because hassium is homologous to osmium, it should occur along with osmium in osmiridium if it occurs in nature. The decay chains of {{sup|271}}Bh and {{sup|271}}Sg are hypothetical and the predicted half-life of this hypothetical hassium isomer is not long enough for any sufficient quantity to remain on Earth.<ref name="natural" /> It is possible that more {{sup|271}}Hs may be deposited on the Earth as the [[Solar System]] travels through the spiral arms of the [[Milky Way]]; this would explain excesses of [[plutonium-239]] found on the ocean floors of the [[Pacific Ocean]] and the [[Gulf of Finland]]. However, minerals enriched with {{sup|271}}Hs are predicted to have excesses of its daughters [[uranium-235]] and lead-207; they would also have different proportions of elements that are formed by spontaneous fission, such as [[krypton]], [[zirconium]], and [[xenon]]. The natural occurrence of hassium in minerals such as molybdenite and osmiride is theoretically possible, but very unlikely.<ref name="natural">{{cite journal|last1=Ivanov|first1=A. V.|title=The possible existence of Hs in nature from a geochemical point of view|journal=Physics of Particles and Nuclei Letters|volume=3|pages=165–168|date=2006|doi=10.1134/S1547477106030046|issue=3|arxiv = nucl-th/0604052 |bibcode = 2006PPNL....3..165I |s2cid=118908703}}</ref>

In 2004, JINR started a search for natural hassium in the [[Modane Underground Laboratory]] in [[Modane]], [[Auvergne-Rhône-Alpes]], France; this was done underground to avoid interference and false positives from [[cosmic ray]]s.<ref name="Emsley2011" /> In 2008–09, an experiment run in the laboratory resulted in detection of several registered events of neutron multiplicity (number of emitted free neutrons after a nucleus is hit by a neutron and fissioned) above three in natural osmium, and in 2012–13, these findings were reaffirmed in another experiment run in the laboratory. These results hinted natural hassium could potentially exist in nature in amounts that allow its detection by the means of analytical chemistry, but this conclusion is based on an explicit assumption that there is a long-lived hassium isotope to which the registered events could be attributed.<ref>{{cite report|url=https://fdocuments.net/document/joule-activity-report.html|title=Report on JINR activities and tasks accomplished in 2013 in Laboratoire Souterrain de Modane|editor-last=Yakushev|editor-first=E.|date=2013|last=Sokol|first=E.|publisher=[[Joint Institute for Nuclear Research]]|access-date=2020-07-10|archive-date=10 July 2020|archive-url=https://web.archive.org/web/20200710131658/https://fdocuments.net/document/joule-activity-report.html|url-status=live}}</ref>

Since {{sup|292}}Hs may be particularly stable against alpha decay and spontaneous fission, it was considered as a candidate to exist in nature. This nuclide, however, is predicted to be very unstable toward beta decay and any [[beta-stability line|beta-stable]] isotopes of hassium such as {{sup|286}}Hs would be too unstable in the other decay channels to be observed in nature.<ref name="48Ca">{{cite journal |last=Oganessian|first=Yu.|title=Heaviest nuclei from {{sup|48}}Ca-induced reactions|date=2007 |journal=[[Journal of Physics G: Nuclear and Particle Physics]]|volume=34|issue=4|page=R235|doi=10.1088/0954-3899/34/4/R01|bibcode=2007JPhG...34R.165O |url=https://www.nucleonica.com/wiki/images/4/41/Oganessian.pdf |access-date=28 December 2018 |url-status=live|archive-date=9 August 2017|archive-url=https://web.archive.org/web/20170809112113/https://www.nucleonica.com/wiki/images/4/41/Oganessian.pdf}}</ref> A 2012 search for {{sup|292}}Hs in nature along with its [[Homologous series|homologue]] osmium at the Maier-Leibnitz Laboratory in [[Garching bei München|Garching]], [[Bavaria]], Germany, was unsuccessful, setting an upper limit to its abundance at {{val|3|e=-15|u=grams}} of hassium per gram of osmium.<ref name="spectrometry">{{cite journal|last1=Ludwig|first1=P. |last2=Faestermann|first2=T.|last3=Korschinek|first3=G.|last4=Rugel|first4=G.|last5=Dillmann|first5=I. |last6=Fimiani|first6=L.|last7=Bishop|first7=S.|last8=Kumar|first8=P.|display-authors=3 |title=Search for superheavy elements with 292 ≤ A ≤ 310 in nature with accelerator mass spectrometry|date=2012 |journal=Physical Review C|volume=85|issue=2|pages=024315{{hyphen}}1–024315{{hyphen}}8 |doi=10.1103/PhysRevC.85.024315 |url=https://www.nucastro.ph.tum.de/fileadmin/tuphena/www/pubs/e024315.pdf |access-date=28 December 2018|archive-url=https://web.archive.org/web/20181228223425/https://www.nucastro.ph.tum.de/fileadmin/tuphena/www/pubs/e024315.pdf |archive-date=28 December 2018|url-status=live}}</ref>

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