View source for Hassium

== Discovery ==

{{See also|Discovery of the chemical elements|Timeline of chemical element discoveries}}
[[File:Apparatus for creation of superheavy elements en.svg|alt=Apparatus for creating superheavy elements|right|thumb|upright=2.00|Scheme of an apparatus for creating superheavy elements, based on the Dubna Gas-Filled Recoil Separator set up in the [[Flerov Laboratory of Nuclear Reactions]] in JINR. The trajectory within the detector and the beam focusing apparatus changes because of a [[magnetic dipole|dipole magnet]] in the former and [[quadrupole magnet]]s in the latter.<ref>{{Cite journal|last1=Aksenov|first1=N. V.|last2=Steinegger|first2=P.|last3=Abdullin|first3=F. Sh.|last4=Albin|first4=Yury V.|last5=Bozhikov|first5=Gospodin A.|last6=Chepigin|first6=Viktor I. |last7=Eichler|first7=Robert|last8=Lebedev|first8=Vyacheslav Ya.|last9=Madumarov|first9=Alexander Sh.|last10=Malyshev|first10=Oleg N.|last11=Petrushkin|first11=Oleg V.|display-authors=3|date=2017|title=On the volatility of nihonium (Nh, Z = 113)|journal=The European Physical Journal A|volume=53|issue=7|page=158|doi=10.1140/epja/i2017-12348-8|bibcode=2017EPJA...53..158A|s2cid=125849923|issn=1434-6001}}</ref>]]

=== Cold fusion ===

Nuclear reactions used in the 1960s resulted in high excitation energies that required expulsion of four or five neutrons; these reactions used targets made of elements with high atomic numbers to maximize the size difference between the two nuclei in a reaction. While this increased the chance of fusion due to the lower electrostatic repulsion between target and projectile, the formed compound nuclei often broke apart and did not survive to form a new element. Moreover, fusion inevitably produces neutron-poor nuclei, as heavier elements need more neutrons per proton for stability;{{efn|Generally, heavier nuclei require more neutrons because as the number of protons increases, so does electrostatic repulsion between them. This repulsion is balanced by the binding energy generated by the strong interaction between quarks within nucleons; it is enough to hold the quarks together in a nucleon together and some of it is left for binding of different nucleons. The more nucleons in a nucleus, the more energy there is for binding the nucleons (greater total binding energy does not necessarily mean greater binding energy per nucleon).<ref>{{Cite web |date=2019 |url=https://inchemistry.acs.org/content/inchemistry/en/atomic-news/modern-alchemy-creating-superheavy-elements.html |last=Poole-Sawyer |first=J. |title=Modern Alchemy: Creating Superheavy Elements |website=[[inChemistry]] |publisher=[[American Chemical Society]] |access-date=2020-01-27 |archive-date=27 January 2020 |archive-url=https://web.archive.org/web/20200127134511/https://inchemistry.acs.org/content/inchemistry/en/atomic-news/modern-alchemy-creating-superheavy-elements.html |url-status=live }}</ref> However, having too many neutrons per proton, while decreasing electrostatic repulsion per nucleon, results in beta decay.<ref>{{Cite web|title=Beta Decay|url=https://www2.lbl.gov/abc/wallchart/chapters/03/2.html|access-date=2020-08-28|work=Guide to the Nuclear Wall Chart|publisher=[[Lawrence Berkeley National Laboratory]]|archive-date=16 December 2017|archive-url=https://web.archive.org/web/20171216223958/http://www2.lbl.gov/abc/wallchart/chapters/03/2.html|url-status=live}}</ref>}} therefore, the necessary ejection of neutrons results in final products that are typically shorter-lived. As such, light beams (six to ten protons) allowed synthesis of elements only up to [[Seaborgium|106]].<ref name="Oganessian122">{{Cite journal|last=Oganessian|first=Yu.|date=2012|title=Nuclei in the "Island of Stability" of Superheavy Elements|journal=Journal of Physics: Conference Series|volume=337|issue=1|pages=012005-1–012005-6|doi=10.1088/1742-6596/337/1/012005|bibcode=2012JPhCS.337a2005O|issn=1742-6596|doi-access=free}}</ref>

To advance to heavier elements, Soviet physicist [[Yuri Oganessian]] at [[Joint Institute for Nuclear Research]] (JINR) in [[Dubna]], [[Moscow Oblast]], [[Russian SFSR]], [[Soviet Union]], proposed a different mechanism, in which the bombarded nucleus would be lead-208, which has [[Magic number (physics)|magic numbers]] of protons and neutrons, or another nucleus close to it.<ref name="Oganessian04">{{Cite journal |last=Oganessian|first=Yu. Ts. |date=2004|title=Superheavy elements|journal=Pure and Applied Chemistry |volume=76|issue=9|pages=1717–1718|doi=10.1351/pac200476091715|issn=1365-3075|doi-access=free}}</ref> Each proton and neutron has a fixed [[rest energy]]; those of all protons are equal and so are those of all neutrons. In a nucleus, some of this energy is diverted to binding protons and neutrons; if a nucleus has a magic number of protons and/or neutrons, then even more of its rest energy is diverted, which makes the nuclide more stable. This additional stability requires more energy for an external nucleus to break the existing one and penetrate it.<ref name="coldfusion77">{{Cite web|url=http://n-t.ru/ri/ps/pb106.htm|title=Популярная библиотека химических элементов. Сиборгий (экавольфрам)|trans-title=Popular library of chemical elements. Seaborgium (eka-tungsten)|language=ru|website=n-t.ru|access-date=2020-01-07|archive-date=23 August 2011|archive-url=https://web.archive.org/web/20110823090114/http://n-t.ru/ri/ps/pb106.htm|url-status=live}} Reprinted from {{cite book|author=<!--none-->|date=1977|title=Популярная библиотека химических элементов. Серебро — Нильсборий и далее|chapter=Экавольфрам|trans-title=Popular library of chemical elements. Silver through nielsbohrium and beyond|trans-chapter=Eka-tungsten|language=ru|publisher=[[Nauka (publisher)|Nauka]]}}</ref> More energy diverted to binding nucleons means less rest energy, which in turn means less mass (mass is proportional to rest energy). More equal atomic numbers of the reacting nuclei result in greater electrostatic repulsion between them, but the lower [[mass excess]] of the target nucleus balances it.<ref name="Oganessian04" /> This leaves less excitation energy for the new compound nucleus, which necessitates fewer neutron ejections to reach a stable state.<ref name="coldfusion77" /> Due to this energy difference, the former mechanism became known as "hot fusion" and the latter as "cold fusion".<ref>{{Cite journal|last=Oganessian|first=Yu. Ts.|date=2000|title=Route to islands of stability of superheavy elements|journal=Physics of Atomic Nuclei |volume=63|issue=8|page=1320|doi=10.1134/1.1307456|bibcode=2000PAN....63.1315O|s2cid=121690628|issn=1063-7788}}</ref>

Cold fusion was first declared successful in 1974 at JINR, when it was tested for synthesis of the yet-undiscovered element{{spaces}}106.<ref name="coldfusion77" /> These new nuclei were projected to decay via spontaneous fission. The physicists at JINR concluded element 106 was produced in the experiment because no fissioning nucleus known at the time showed parameters of fission similar to what was observed during the experiment and because changing either of the two nuclei in the reactions negated the observed effects. Physicists at Lawrence Berkeley Laboratory (LBL; originally Radiation Laboratory, RL, and later [[Lawrence Berkeley National Laboratory]], LBNL) of the [[University of California, Berkeley|University of California]] in [[Berkeley, California|Berkeley]], [[California]], United States, also expressed great interest in the new technique.<ref name="coldfusion77" /> When asked about how far this new method could go and if lead targets were a physics' [[Klondike Gold Rush|Klondike]], Oganessian responded, "Klondike may be an exaggeration [...] But soon, we will try to get elements [[Bohrium|107]]{{spaces}}... 108 in these reactions."<ref name="coldfusion77" />

=== Reports ===

Synthesis of element{{spaces}}108 was first attempted in 1978 by a team led by Oganessian at JINR. The team used a reaction that would generate element{{spaces}}108, specifically, the isotope {{sup|270}}108,{{Efn|The superscript number to the left of a chemical symbol refers to the mass of the nuclide; for instance, {{sup|48}}Ca is [[calcium-48]]. In superheavy element research, elements that have not gotten a name and a symbol, are often called by their atomic number in lieu of symbols; if a symbol has been assigned and the number is to be displayed, it is written in subscript to the left of the symbol. {{sup|270}}108 would be {{sup|270}}Hs or {{nuclide|hassium|270}} or hassium-270 in modern nomenclature.}} from fusion of [[radium]] (specifically, the isotope {{nowrap|{{Nuclide|radium|226}})}} and [[calcium]] {{nowrap|({{Nuclide|calcium|48}})}}. The researchers were uncertain in interpreting their data, and their paper did not unambiguously claim to have discovered the element.<ref>{{cite report |first1=Yu. Ts. |last1=Oganessian |first2=G. M. |last2=Ter-Akopian |first3=A. A. |last3=Pleve |display-authors=etal |year=1978 |title=Опыты по синтезу 108 элемента в реакции {{sup|226}}Ra + {{sup|48}}Ca |trans-title=Experiments on synthesis of element{{spaces}}108 in the {{sup|226}}Ra+{{sup|48}}Ca reaction |publisher=[[Joint Institute for Nuclear Research]] |url=https://inis.iaea.org/collection/NCLCollectionStore/_Public/13/643/13643968.pdf |access-date=8 June 2018 |language=ru |archive-date=15 March 2020 |archive-url=https://web.archive.org/web/20200315080910/https://inis.iaea.org/collection/NCLCollectionStore/_Public/13/643/13643968.pdf |url-status=live }}</ref> The same year, another team at JINR investigated the possibility of synthesis of element{{spaces}}108 in reactions between [[lead]] {{nowrap|({{Nuclide|lead|208}})}} and [[iron]] {{nowrap|({{Nuclide|iron|58}})}}; they were uncertain in interpreting the data, suggesting the possibility that element{{spaces}}108 had not been created.<ref>{{Cite report|last1=Orlova|first1=O. A.|last2=Pleve|first2=A. A.|last3=Ter-Akop'yan|first3=G. M.|last4=Tret'yakova|first4=S. P.|last5=Chepigin|first5=V. I.|last6=Cherepanov|first6=E. A.|display-authors=3|date=1979|title=Опыты по синтезу 108 элемента в реакции {{sup|208}}Pb + {{sup|58}}Fe|trans-title=Experiments on the synthesis of element 108 in the {{sup|208}}Pb + {{sup|58}}Fe reaction|url=https://inis.iaea.org/collection/NCLCollectionStore/_Public/10/486/10486434.pdf|language=ru|publisher=Joint Institute for Nuclear Research|access-date=2020-08-28|archive-date=11 March 2020|archive-url=https://web.archive.org/web/20200311041124/https://inis.iaea.org/collection/NCLCollectionStore/_Public/10/486/10486434.pdf|url-status=live}}</ref>
[[File:GSI, Darmstadt, Juli 2015 (4).JPG|thumb|upright=1.15|alt=GSI's particle accelerator UNILAC|GSI's linear [[particle accelerator]] UNILAC, where hassium was discovered<ref>{{Cite web|title=Timeline—GSI|url=https://www.gsi.de/en/about_us/50_years_gsi/timeline_1969_2019.htm|publisher=[[GSI Helmholtz Centre for Heavy Ion Research]]|access-date=2019-12-10|archive-date=5 August 2020|archive-url=https://web.archive.org/web/20200805184050/https://www.gsi.de/en/about_us/50_years_gsi/timeline_1969_2019.htm|url-status=live}}</ref> and where its chemistry was first observed<ref>{{Cite news|last=Preuss|first=P.|date=2001|url=https://www2.lbl.gov/Science-Articles/Archive/108-chemistry.html|title=Hassium becomes heaviest element to have its chemistry studied|publisher=Lawrence Berkeley National Laboratory|access-date=2019-12-10|archive-date=10 December 2019|archive-url=https://web.archive.org/web/20191210155135/https://www2.lbl.gov/Science-Articles/Archive/108-chemistry.html|url-status=live}}</ref>|left]]

In 1983, new experiments were performed at JINR.{{sfn|Barber et al.|1993|p=1790}} The experiments probably resulted in the synthesis of element{{spaces}}108; [[bismuth]] {{nowrap|({{Nuclide|bismuth|209}})}} was bombarded with [[manganese]] {{nowrap|({{Nuclide|manganese|55}})}} to obtain {{sup|263}}108, lead ({{sup|207, 208}}Pb) was bombarded with iron ({{sup|58}}Fe) to obtain {{sup|264}}108, and [[californium]] {{nowrap|({{Nuclide|californium|249}})}} was bombarded with [[neon]] {{nowrap|({{Nuclide|neon|22}})}} to obtain {{sup|270}}108.<ref name="Emsley2011" /> These experiments were not claimed as a discovery and Oganessian announced them in a conference rather than in a written report.{{sfn|Barber et al.|1993|p=1790}}

In 1984, JINR researchers in Dubna performed experiments set up identically to the previous ones; they bombarded bismuth and lead targets with ions of manganese and iron, respectively. Twenty-one spontaneous fission events were recorded; the researchers concluded they were caused by {{sup|264}}108.{{sfn|Barber et al.|1993|p=1791}}

Later in 1984, a research team led by [[Peter Armbruster]] and [[Gottfried Münzenberg]] at [[Gesellschaft für Schwerionenforschung]] (GSI; ''Institute for Heavy Ion Research'') in [[Darmstadt]], [[Hesse]], [[West Germany]], tried to create element{{spaces}}108. The team bombarded a lead ({{sup|208}}Pb) target with accelerated iron ({{sup|58}}Fe) nuclei.<ref name="84Mu01">{{Cite journal|doi=10.1007/BF01421260|title=The identification of element 108|year=1984|author=Münzenberg, G.|journal=Zeitschrift für Physik A|volume=317|page=235|last2=Armbruster|first2=P.|last3=Folger|first3=H.|last4=Heßberger|first4=P. F.|last5=Hofmann|first5=S.|last6=Keller|first6=J.|last7=Poppensieker|first7=K.|last8=Reisdorf|first8=W.|last9=Schmidt|first9=K. -H.|bibcode = 1984ZPhyA.317..235M|issue=2 }}</ref> GSI's experiment to create element{{spaces}}108 was delayed until after their creation of [[meitnerium|element{{spaces}}109]] in 1982, as prior calculations had suggested that [[even and odd atomic nuclei#Even proton, even neutron|even–even]] isotopes of element{{spaces}}108 would have spontaneous fission half-lives of less than one [[microsecond]], making them difficult to detect and identify.<ref name="GSIrecollection" /> The element{{spaces}}108 experiment finally went ahead after {{sup|266}}109 had been synthesized and was found to decay by alpha emission, suggesting that isotopes of element{{spaces}}108 would do likewise, and this was corroborated by an experiment aimed at synthesizing isotopes of element{{spaces}}106. GSI reported synthesis of three atoms of {{sup|265}}108. Two years later, they reported synthesis of one atom of the even–even {{sup|264}}108.<ref name="GSIrecollection">{{cite journal |last1=Hofmann |first1=S. |date=2016 |title=The discovery of elements 107 to 112 |url=https://www.epj-conferences.org/articles/epjconf/pdf/2016/26/epjconf-NS160-06001.pdf |journal=EPJ Web Conf. |volume=131 |doi=10.1051/epjconf/201613106001 |access-date=23 September 2019 |pages=4–5 |bibcode=2016EPJWC.13106001H |doi-access=free |archive-date=1 February 2021 |archive-url=https://web.archive.org/web/20210201101405/https://www.epj-conferences.org/articles/epjconf/pdf/2016/26/epjconf-NS160-06001.pdf |url-status=live }}</ref>

=== Arbitration ===

In 1985, the [[International Union of Pure and Applied Chemistry]] (IUPAC) and the [[International Union of Pure and Applied Physics]] (IUPAP) formed the Transfermium Working Group (TWG) to assess [[discovery of the chemical elements|discoveries]] and establish final names for elements with atomic numbers greater than 100. The party held meetings with delegates from the three competing institutes; in 1990, they established criteria for recognition of an element and in 1991, they finished the work of assessing discoveries and disbanded. These results were published in 1993.{{sfn|Barber et al.|1993|p=1757}}

According to the report, the 1984 works from JINR and GSI simultaneously and independently established synthesis of element{{spaces}}108. Of the two 1984 works, the one from GSI was said to be sufficient as a discovery on its own. The JINR work, which preceded the GSI one, "very probably" displayed synthesis of element{{spaces}}108. However, that was determined in retrospect given the work from Darmstadt; the JINR work focused on chemically identifying remote granddaughters of element{{spaces}}108 isotopes (which could not exclude the possibility that these daughter isotopes had other progenitors), while the GSI work clearly identified the decay path of those element{{spaces}}108 isotopes. The report concluded that the major credit should be awarded to GSI.{{sfn|Barber et al.|1993|p=1791}} In written responses to this ruling, both JINR and GSI agreed with its conclusions. In the same response, GSI confirmed that they and JINR were able to resolve all conflicts between them.<ref name="1993 responses">{{cite web |url=https://www.gsi.de/en/work/research/nustarenna/nustarenna_divisions/she_physik/research/super_heavy_elements/element_107_109.htm |title=GSI - Element 107-109 |website=GSI Helmholtz Centre for Heavy Ion Research |access-date=29 September 2019 |date=2012 |archive-date=29 September 2019 |archive-url=https://web.archive.org/web/20190929155340/https://www.gsi.de/en/work/research/nustarenna/nustarenna_divisions/she_physik/research/super_heavy_elements/element_107_109.htm }}</ref>

=== Naming ===

{{See also|Transfermium Wars}}

Historically, a newly discovered element was named by its discoverer. The first regulation came in 1947, when IUPAC decided naming required regulation in case there are conflicting names.<ref name="IUPAC2002" />{{Efn|This was intended to resolve not only any future conflicts, but also a number of ones that existed back then: [[beryllium]]/glucinium, [[niobium]]/columbium, [[lutetium|lutecium]]/cassiopeium, [[hafnium]]/celtium, [[tungsten]]/wolfram, and [[protactinium]](protoactinium)/brevium.<ref name="IUPAC2002" />}} These matters were to be resolved by the Commission of Inorganic Nomenclature and the [[Commission on Isotopic Abundances and Atomic Weights|Commission of Atomic Weights]]. They would review the names in case of a conflict and select one; the decision would be based on a number of factors, such as usage, and would not be an indicator of priority of a claim. The two commissions would recommend a name to the IUPAC Council, which would be the final authority.<ref name="IUPAC2002" /> The discoverers held the right to name an element, but their name would be subject to approval by IUPAC.<ref name="IUPAC2002" /> The Commission of Atomic Weights distanced itself from element naming in most cases.<ref name="IUPAC2002">{{Cite journal|last=Koppenol|first=W. H.|date=2002|title=Naming of new elements (IUPAC Recommendations 2002)|journal=Pure and Applied Chemistry|volume=74|issue=5|page=788|doi=10.1351/pac200274050787|s2cid=95859397|issn=1365-3075|url=http://doc.rero.ch/record/295589/files/pac200274050787.pdf|access-date=8 September 2020|archive-date=11 March 2023|archive-url=https://web.archive.org/web/20230311205341/https://doc.rero.ch/record/295589/files/pac200274050787.pdf|url-status=live}}</ref>

In [[Mendeleev's predicted elements|Mendeleev's nomenclature for unnamed and undiscovered elements]], hassium would be called "eka-[[osmium]]", as in "the first element below osmium in the periodic table" (from [[Sanskrit]] ''eka'' meaning "one"). In 1979, IUPAC published recommendations according to which the element was to be called "unniloctium" (symbol "Uno"),<ref name="IUPAC1979">{{cite journal|last1=Chatt |first1=J.|journal=Pure and Applied Chemistry|date=1979|volume=51|issue=2 |pages=381–384|title=Recommendations for the naming of elements of atomic numbers greater than 100 |doi=10.1351/pac197951020381|doi-access=free}}</ref> a [[systematic element name]] as a [[placeholder name|placeholder]] until the element was discovered and the discovery then confirmed, and a permanent name was decided. Although these recommendations were widely followed in the chemical community, the competing physicists in the field ignored them.<ref>{{cite journal|last1=Öhrström|first1=L.|last2=Holden|first2=N. E.|date=2016 |title=The Three-Letter Element Symbols|journal=Chemistry International|volume=38 |issue=2|pages=4–8|doi=10.1515/ci-2016-0204|doi-access=free}}</ref>{{sfn|Greenwood|Earnshaw|1997|p=30}} They either called it "element{{spaces}}108", with the symbols ''E108'', ''(108)'' or ''108'', or used the proposed name "hassium".{{sfn|Hoffman|Lee|Pershina|2006|p=1653}}
[[File:Coat of arms of Hesse.svg|thumb|upright=0.6|[[Coat of arms]] of the German state of [[Hesse]], after which hassium is named.

]]

In 1990, in an attempt to break a deadlock in establishing priority of discovery and naming of several elements, IUPAC reaffirmed in its [[IUPAC nomenclature of inorganic chemistry|nomenclature of inorganic chemistry]] that after existence of an element was established, the discoverers could propose a name. (Also, the Commission of Atomic Weights was excluded from the naming process.) The first publication on criteria for an element discovery, released in 1991, specified the need for recognition by TWG.<ref name="IUPAC2002" />

Armbruster and his colleagues, the officially recognized German discoverers, held a naming ceremony for the elements 107 through 109, which had all been recognized as discovered by GSI, on 7{{spaces}}September 1992. For element{{spaces}}108, the scientists proposed the name "hassium".<ref>{{cite web |url=https://www.gsi.de/en/work/research/nustarenna/nustarenna_divisions/she_physik/research/super_heavy_elements/element_107_109.htm |title=GSI—Element 107-109 |work=GSI |publisher=GSI Helmholtz Centre for Heavy Ion Research |access-date=29 September 2019 |date=2012 |archive-date=29 September 2019 |archive-url=https://web.archive.org/web/20190929155340/https://www.gsi.de/en/work/research/nustarenna/nustarenna_divisions/she_physik/research/super_heavy_elements/element_107_109.htm }}</ref> It is derived from the [[Latin]] name ''Hassia'' for the [[States of Germany|German state]] of Hesse where the institute is located.<ref name="Emsley2011" /><ref name="1993 responses" /> This name was proposed to IUPAC in a written response to their ruling on priority of discovery claims of elements, signed 29 September 1992.<ref name="1993 responses" />

The process of naming of element 108 was a part of a larger process of naming a number of elements starting with [[Mendelevium|element 101]]; three teams—JINR, GSI, and LBL—claimed discovery of several elements and the right to name those elements. Sometimes, these claims clashed; since a discoverer was considered entitled to naming of an element, conflicts over priority of discovery often resulted in conflicts over names of these new elements. These conflicts became known as the [[Transfermium Wars]].<ref>{{cite journal|last=Karol|first=P.|date=1994|title=The Transfermium Wars|journal=Chemical & Engineering News|volume=74|issue=22|pages=2–3|doi=10.1021/cen-v072n044.p002|doi-access=free}}</ref> Different suggestions to name the whole set of elements from 101 onward and they occasionally assigned names suggested by one team to be used for elements discovered by another.{{Efn|For example, Armbruster suggested element 107 be named ''nielsbohrium''; JINR used this name for element 105 which they claimed to have discovered. This was meant to honor Oganessian's technique of cold fusion; GSI had asked JINR for permission.{{sfn|Hoffman|Ghiorso|Seaborg|2000|pp=337–338, 384}}}} However, not all suggestions were met with equal approval; the teams openly protested naming proposals on several occasions.{{sfn|Hoffman|Ghiorso|Seaborg|2000|pp=385–394}}

In 1994, IUPAC Commission on Nomenclature of Inorganic Chemistry recommended that element{{spaces}}108 be named "hahnium" (Hn) after German physicist [[Otto Hahn]] so elements named after Hahn and [[Lise Meitner]] (it was recommended element{{spaces}}109 should be named meitnerium, following GSI's suggestion) would be next to each other, honouring their joint discovery of nuclear fission;<ref name="IUPAC94">{{Cite journal|doi=10.1351/pac199466122419|title=Names and symbols of transfermium elements (IUPAC Recommendations 1994)|date=1994|journal=Pure and Applied Chemistry|volume=66|pages=2419–2421|issue=12|author=Inorganic Chemistry Division: Commission on Nomenclature of Inorganic Chemistry|url=http://publications.iupac.org/pac/pdf/1994/pdf/6612x2419.pdf|access-date=2020-08-28|archive-date=11 October 2021|archive-url=https://web.archive.org/web/20211011045418/http://publications.iupac.org/pac/pdf/1994/pdf/6612x2419.pdf|url-status=live}}</ref> IUPAC commented that they felt the German suggestion was obscure.<ref>{{cite journal |last1=Cotton |first1=S. A. |date=1996 |title=After the actinides, then what? |journal=[[Chemical Society Reviews]] |volume=25 |issue=3 |pages=219–227 |doi=10.1039/CS9962500219}}</ref> GSI protested, saying this proposal contradicted the long-standing convention of giving the discoverer the right to suggest a name;<ref name="GSI97">{{cite web |url=http://www-alt.gsi.de/documents/DOC-2003-Jun-35-5.pdf |title=IUPAC verabschiedet Namen für schwere Elemente: GSI-Vorschläge für die Elemente 107 bis 109 akzeptiert |language=de |trans-title=IUPAC adopts names for heavy elements: GSI's suggestions for elements 107 to 109 accepted |date=1997 |website=GSI-Nachrichten |publisher=[[Gesellschaft für Schwerionenforschung]] |access-date=30 June 2019 |archive-url=https://web.archive.org/web/20151223025747/https://www-alt.gsi.de/documents/DOC-2003-Jun-35-5.pdf |archive-date=23 December 2015}}</ref> the [[American Chemical Society]] supported GSI.<ref name="Emsley2011" /> The name "hahnium", albeit with the different symbol Ha, had already been proposed and used by the American scientists for [[dubnium|element{{spaces}}105]], for which they had a discovery dispute with JINR; they thus protested the confusing scrambling of names.<ref>{{Cite web|url=http://www2.lbl.gov/Science-Articles/Archive/seaborgium-dispute.html|title=Naming of element{{spaces}}106 disputed by international committee|last=Yarris|first=L.|year=1994|publisher=[[Lawrence Berkeley Laboratory]]|access-date=September 7, 2016|archive-date=1 July 2016|archive-url=https://web.archive.org/web/20160701203756/http://www2.lbl.gov/Science-Articles/Archive/seaborgium-dispute.html|url-status=live}}</ref> Following the uproar, IUPAC formed an ad hoc committee of representatives from the national adhering organizations of the three countries home to the competing institutions; they produced a new set of names in 1995. Element{{spaces}}108 was again named ''hahnium''; this proposal was also retracted.{{sfn|Hoffman|Ghiorso|Seaborg|2000|pp=392–394}} The final compromise was reached in 1996 and published in 1997; element{{spaces}}108 was named ''hassium'' (Hs).{{sfn|Hoffman|Ghiorso|Seaborg|2000|pp=394–395}} Simultaneously, the name ''dubnium'' (Db; from Dubna, the JINR location) was assigned to element{{spaces}}105, and the name ''hahnium'' was not used for any element.<ref name="Bera1999">{{Cite journal|last=Bera|first=J. K.|year=1999|title=Names of the Heavier Elements |journal=Resonance|volume=4|issue=3|pages=53–61|doi=10.1007/BF02838724|s2cid=121862853}}</ref><ref>{{cite journal | doi=10.1351/pac199769122471|title=Names and symbols of transfermium elements (IUPAC Recommendations 1997) | year=1997 | journal=Pure and Applied Chemistry | volume=69 | pages=2471–2474 | issue=12| doi-access=free }}</ref>{{efn|American physicist [[Glenn T. Seaborg]] suggested that name for element{{spaces}}110 on behalf of LBNL in November 1997 after IUPAC surveyed the three main collaborations (GSI, JINR/[[Lawrence Livermore National Laboratory|LLNL]], and LBNL) on how they thought the element should be named.{{sfn|Hoffman|Ghiorso|Seaborg|2000|pp=396–398}}}}

The official justification for this naming, alongside that of [[darmstadtium]] for element{{spaces}}110, was that it completed a set of geographic names for the location of the GSI; this set had been initiated by 19th-century names [[europium]] and [[germanium]]. This set would serve as a response to earlier naming of [[americium]], californium, and [[berkelium]] for elements discovered in Berkeley. Armbruster commented on this, "this bad tradition{{efn|Similarly, there are names of [[ruthenium]], [[moscovium]], and [[dubnium]] for JINR. The only element discovered by [[RIKEN]] in [[Wakō, Saitama|Wakō]], [[Saitama Prefecture]], Japan, is named [[nihonium]] after a Japanese name of Japan.}} was established by Berkeley. We wanted to do it for Europe."<ref name="PeriodicTales" /> Later, when commenting on the naming of [[copernicium|element{{spaces}}112]], Armbruster said, "I did everything to ensure that we do not continue with German scientists and German towns."<ref name="PeriodicTales">{{cite book |last=Aldersey-Williams |first=H. |author-link=Hugh Aldersey-Williams |title=Periodic Tales |date=2011 |publisher=[[HarperCollins Publishers]] |isbn=978-0-06-182473-9 |pages=396–397|title-link=Periodic Tales }}</ref>

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