Editing Seaborgium (section)

==History==
Following claims of the observation of elements [[rutherfordium|104]] and [[dubnium|105]] in 1970 by [[Albert Ghiorso]] et al. at the [[Lawrence Livermore National Laboratory]], a search for element 106 using oxygen-18 projectiles and the previously used californium-249 target was conducted.<ref name="Transuraniumppl" /> Several 9.1 MeV [[alpha decay]]s were reported and are now thought to originate from element 106, though this was not confirmed at the time. In 1972, the HILAC accelerator received equipment upgrades, preventing the team from repeating the experiment, and data analysis was not done during the shutdown.<ref name="Transuraniumppl">{{cite book|last1=Hoffman|first1=D.C |last2=Ghiorso|first2=A.|last3=Seaborg|first3=G.T.|title=The Transuranium People: The Inside Story |publisher=Imperial College Press|date=2000|isbn=978-1-86094-087-3|pages=300–327}}</ref> This reaction was tried again several years later, in 1974, and the Berkeley team realized that their new data agreed with their 1971 data, to the astonishment of Ghiorso. Hence, element 106 could have actually been discovered in 1971 if the original data was analyzed more carefully.<ref name="Transuraniumppl" />

Two groups claimed [[discovery of the chemical elements|discovery of the element]]. Evidence of element 106 was first reported in 1974 by a Russian research team in [[Dubna]] led by [[Yuri Oganessian]], in which targets of [[lead-208]] and [[lead-207]] were bombarded with accelerated ions of [[chromium-54]]. In total, fifty-one [[spontaneous fission]] events were observed with a half-life between four and ten [[milliseconds]]. After having ruled out nucleon [[Nuclear reaction#Transfer reactions|transfer reactions]] as a cause for these activities, the team concluded that the most likely cause of the activities was the spontaneous fission of isotopes of element 106. The isotope in question was first suggested to be seaborgium-259, but was later corrected to seaborgium-260.<ref name="93TWG">{{Cite journal
|doi=10.1351/pac199365081757
|title=Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements
|year=1993
|journal=Pure and Applied Chemistry
|volume=65
|pages=1757
|last1=Barber |first1=R. C.
|last2=Greenwood|first2=N. N.
|last3=Hrynkiewicz|first3=A. Z.
|last4=Jeannin|first4=Y. P.
|last5=Lefort|first5=M.
|last6=Sakai|first6=M.
|last7=Ulehla|first7=I.
|last8=Wapstra|first8=A. P.
|last9=Wilkinson|first9=D. H.
|issue=8|s2cid=195819585
|doi-access=free
}}</ref>

:{{nuclide|link=yes|lead|208}} + {{nuclide|link=yes|chromium|54}} → {{nuclide|link=yes|seaborgium|260}} + 2 {{SubatomicParticle|link=yes|neutron}}
:{{nuclide|link=yes|lead|207}} + {{nuclide|chromium|54}} → {{nuclide|seaborgium|260}} + {{SubatomicParticle|neutron}}

A few months later in 1974, researchers including Glenn T. Seaborg, [[Carol Alonso]] and Albert Ghiorso at the [[University of California, Berkeley]], and E. Kenneth Hulet from the Lawrence Livermore National Laboratory, also synthesized the element<ref>{{cite journal|first1=A. |last1=Ghiorso |first2=J. M. |last2=Nitschke |first3=J. R. |last3=Alonso |first4=C. T. |last4=Alonso |first5=M. |last5=Nurmia |first6=G. T. |last6=Seaborg |first7=E. K. |last7=Hulet |first8=R. W. |last8=Lougheed |journal=Physical Review Letters |title=Element 106 |volume=33 |issue=25 |page=1490 |date=December 1974 |doi=10.1103/PhysRevLett.33.1490 |bibcode=1974PhRvL..33.1490G |doi-access=free }}</ref> by bombarding a [[californium]]-249 target with [[oxygen-18]] ions, using equipment similar to that which had been used for the synthesis of [[rutherfordium|element 104]] five years earlier, observing at least seventy [[alpha decay]]s, seemingly from the isotope seaborgium-263m with a half-life of {{val|0.9|0.2}} seconds. The alpha daughter rutherfordium-259 and granddaughter nobelium-255 had previously been synthesised and the properties observed here matched with those previously known, as did the intensity of their production. The [[cross-section (physics)|cross-section]] of the reaction observed, 0.3&nbsp;[[barn (unit)|nanobarns]], also agreed well with theoretical predictions. These bolstered the assignment of the alpha decay events to seaborgium-263m.<ref name="93TWG" />

:{{nuclide|link=yes|californium|249}} + {{nuclide|link=yes|oxygen|18}} → {{nuclide|link=yes|seaborgium|263m}} + 4 {{SubatomicParticle|link=yes|10neutron}} → {{nuclide|link=yes|rutherfordium|259}} + {{SubatomicParticle|link=yes|alpha}} → {{nuclide|link=yes|nobelium|255}} + {{SubatomicParticle|link=yes|alpha}}

A dispute thus arose from the initial competing claims of discovery, though unlike the case of the synthetic elements up to [[dubnium|element 105]], neither team of discoverers chose to announce proposed names for the new elements, thus averting an [[element naming controversy]] temporarily. The dispute on discovery, however, dragged on until 1992, when the IUPAC/IUPAP Transfermium Working Group (TWG), formed to put an end to the controversy by making conclusions regarding discovery claims for elements 101 to [[copernicium|112]], concluded that the Soviet synthesis of seaborgium-260 was not convincing enough, "lacking as it is in yield curves and angular selection results", whereas the American synthesis of seaborgium-263 was convincing due to its being firmly anchored to known daughter nuclei. As such, the TWG recognised the Berkeley team as official discoverers in their 1993 report.<ref name="93TWG" />

[[File:Seaborg in lab - restoration.jpg|thumb|upright=1.0|Element 106 was named after [[Glenn T. Seaborg]], a pioneer in the discovery of [[synthetic element]]s, with the name ''seaborgium'' (Sg).]]
[[File:Chemist Glenn Seaborg (14678590682).jpg|thumb|right|Seaborg pointing to the element named after him on the periodic table]]
Seaborg had previously suggested to the TWG that if Berkeley was recognised as the official discoverer of elements 104 and 105, they might propose the name ''kurchatovium'' (symbol Kt) for element 106 to honour the Dubna team, which had proposed this name for element 104 after [[Igor Kurchatov]], the former head of the [[Soviet nuclear research]] programme. However, due to the worsening relations between the competing teams after the publication of the TWG report (because the Berkeley team vehemently disagreed with the TWG's conclusions, especially regarding element 104), this proposal was dropped from consideration by the Berkeley team.<ref name="transuranium">Hoffman, D.C., Ghiorso, A., Seaborg, G. T. The Transuranium People: The Inside Story, (2000), 369–399</ref> After being recognized as official discoverers, the Berkeley team started deciding on a name in earnest:

{{blockquote|...we were given credit for the discovery and the accompanying right to name the new element. The eight members of the Ghiorso group suggested a wide range of names honoring Isaac Newton, Thomas Edison, Leonardo da Vinci, Ferdinand Magellan, the mythical Ulysses, George Washington, and Finland, the native land of a member of the team. There was no focus and no front-runner for a long period.<br>Then one day Al [Ghiorso] walked into my office and asked what I thought of naming element 106 "seaborgium." I was floored.<ref name="vanderkrogt">{{cite web |url=http://elements.vanderkrogt.net/element.php?sym=sg |title=106 Seaborgium |publisher=Elements.vanderkrogt.net |access-date=12 September 2008 |archive-date=23 January 2010 |archive-url=https://web.archive.org/web/20100123003450/http://elements.vanderkrogt.net/element.php?sym=Sg |url-status=live }}</ref>|author=Glenn Seaborg}}

Seaborg's son Eric remembered the naming process as follows:<ref name="EricSeaborg" />

{{blockquote|With eight scientists involved in the discovery suggesting so many good possibilities, Ghiorso despaired of reaching consensus, until he awoke one night with an idea. He approached the team members one by one, until seven of them had agreed. He then told his friend and colleague of 50 years: "We have seven votes in favor of naming element 106 seaborgium. Will you give your consent?" My father was flabbergasted, and, after consulting my mother, agreed.<ref name="EricSeaborg">{{cite journal|first = Seaborg|last = Eric|date = 2003|title = Seaborgium|journal = Chemical and Engineering News|url = http://pubs.acs.org/cen/80th/seaborgium.html|volume = 81|issue = 36|access-date = 2017-05-05|archive-date = 2019-04-18|archive-url = https://web.archive.org/web/20190418174239/http://pubs.acs.org/cen/80th/seaborgium.html|url-status = live}}</ref>|author=Eric Seaborg}}

The name ''seaborgium'' and symbol ''Sg'' were announced at the 207th national meeting of the [[American Chemical Society]] in March 1994 by Kenneth Hulet, one of the co-discovers.<ref name="vanderkrogt" /> However, [[IUPAC]] resolved in August 1994 that an element could not be named after a living person, and Seaborg was still alive at the time. Thus, in September 1994, IUPAC recommended a set of names in which the names proposed by the three laboratories (the third being the [[GSI Helmholtz Centre for Heavy Ion Research]] in [[Darmstadt]], [[Germany]]) with competing claims to the discovery for elements 104 to [[meitnerium|109]] were shifted to various other elements, in which ''rutherfordium'' (Rf), the Berkeley proposal for element 104, was shifted to element 106, with ''seaborgium'' being dropped entirely as a name.<ref name="transuranium" />

<div style="float:center; margin:0; font-size:85%;">
{|class="wikitable"
|+ Summary of element naming proposals and final decisions for elements 101–112 (those covered in the TWG report)<ref name="transuranium" />
|-
! Atomic number !! Systematic !! American !! Russian !! German !! Compromise 92 !! IUPAC 94 !! ACS 94 !! IUPAC 95 !! IUPAC 97 !! Present
|-
| 101 || unnilunium || mendelevium || {{sdash}} || {{sdash}} || mendelevium || mendelevium || mendelevium || mendelevium || mendelevium || mendelevium
|-
| 102 || unnilbium || nobelium || joliotium || {{sdash}} || joliotium || nobelium || nobelium || flerovium || nobelium || nobelium
|-
| 103 || unniltrium || lawrencium || rutherfordium || {{sdash}} || lawrencium || lawrencium || lawrencium || lawrencium || lawrencium || lawrencium
|-
| 104 || unnilquadium || rutherfordium || kurchatovium || {{sdash}} || meitnerium || dubnium || rutherfordium || dubnium || rutherfordium || rutherfordium
|-
| 105 || unnilpentium || hahnium || nielsbohrium || {{sdash}} || kurchatovium || joliotium || hahnium || joliotium || dubnium || dubnium
|-
| 106 || unnilhexium || seaborgium || {{sdash}} || {{sdash}} || rutherfordium || rutherfordium || seaborgium || seaborgium || seaborgium || seaborgium
|-
| 107 || unnilseptium || {{sdash}} || {{sdash}} || nielsbohrium || nielsbohrium || bohrium || nielsbohrium || nielsbohrium || bohrium || bohrium
|-
| 108 || unniloctium || {{sdash}} || {{sdash}} || hassium || hassium || hahnium || hassium || hahnium || hassium || hassium
|-
| 109 || unnilennium || {{sdash}} || {{sdash}} || meitnerium || hahnium || meitnerium || meitnerium || meitnerium || meitnerium || meitnerium
|-
| 110 || ununnilium || hahnium || becquerelium || darmstadtium || {{sdash}} || {{sdash}} || {{sdash}} || {{sdash}} || {{sdash}} || darmstadtium
|-
| 111 || unununium || {{sdash}} || {{sdash}} || roentgenium || {{sdash}} || {{sdash}} || {{sdash}} || {{sdash}} || {{sdash}} || roentgenium
|-
| 112 || ununbium || {{sdash}} || {{sdash}} || copernicium || {{sdash}} || {{sdash}} || {{sdash}} || {{sdash}} || {{sdash}} || copernicium
|}
</div>

This decision ignited a firestorm of worldwide protest for disregarding the historic discoverer's right to name new elements, and against the new retroactive rule against naming elements after living persons; the American Chemical Society stood firmly behind the name ''seaborgium'' for element 106, together with all the other American and German naming proposals for elements 104 to 109, approving these names for its journals in defiance of IUPAC.<ref name="transuranium" /> At first, IUPAC defended itself, with an American member of its committee writing: "Discoverers don't have a right to name an element. They have a right to suggest a name. And, of course, we didn't infringe on that at all." However, Seaborg responded:

{{blockquote|This would be the first time in history that the acknowledged and uncontested discoverers of an element are denied the privilege of naming it.<ref name="vanderkrogt" />|author=Glenn Seaborg}}

Bowing to public pressure, IUPAC proposed a different compromise in August 1995, in which the name ''seaborgium'' was reinstated for element 106 in exchange for the removal of all but one of the other American proposals, which met an even worse response. Finally, IUPAC rescinded these previous compromises and made a final, new recommendation in August 1997, in which the American and German proposals for elements 104 to 109 were all adopted, including ''seaborgium'' for element 106, with the single exception of element 105, named ''dubnium'' to recognise the contributions of the Dubna team to the experimental procedures of transactinide synthesis. This list was finally accepted by the American Chemical Society, which wrote:<ref name="transuranium" />

{{blockquote|In the interest of international harmony, the Committee reluctantly accepted the name 'dubnium' for element 105 in place of 'hahnium' [the American proposal], which has had long-standing use in literature. We are pleased to note that 'seaborgium' is now the internationally approved name for element 106.<ref name="transuranium" />|author=American Chemical Society}}

Seaborg commented regarding the naming:

{{blockquote|I am, needless to say, proud that U.S. chemists recommended that element 106, which is placed under tungsten (74), be called 'seaborgium.' I was looking forward to the day when chemical investigators will refer to such compounds as seaborgous chloride, seaborgic nitrate, and perhaps, sodium seaborgate.<br>This is the greatest honor ever bestowed upon me—even better, I think, than winning the Nobel Prize.{{efn|Seaborg had in fact previously won the 1951 [[Nobel Prize in Chemistry]] together with [[Edwin McMillan]] for "their discoveries in the chemistry of the first transuranium elements".<ref name="Nobel Prize">{{cite web |title=The Nobel Prize in Chemistry 1951 |url=http://nobelprize.org/nobel_prizes/chemistry/laureates/1951/index.html |publisher=[[Nobel Foundation]] |access-date=August 26, 2012 |archive-date=November 4, 2008 |archive-url=https://web.archive.org/web/20081104054538/http://nobelprize.org/nobel_prizes/chemistry/laureates/1951/index.html |url-status=live }}</ref>}} Future students of chemistry, in learning about the periodic table, may have reason to ask why the element was named for me, and thereby learn more about my work.<ref name="vanderkrogt" />|author=Glenn Seaborg}}

Seaborg died a year and a half later, on 25 February 1999, at the age of 86.<ref name="vanderkrogt" />