Rutherfordium: Difference between revisions

Rutherfordium was reportedly [[discovery of the chemical elements|first detected]] in 1964 at the [[Joint Institute for Nuclear Research]] at [[Dubna]] ([[Soviet Union]] at the time). Researchers there bombarded a [[plutonium]]-242 target with [[neon]]-22 [[ion]]s; a [[spontaneous fission]] activity with half-life 0.3&nbsp;±&nbsp;0.1&nbsp;seconds was detected and assigned to ²⁶⁰104. Later work found no isotope of element 104 with this half-life, so that this assignment must be considered incorrect.<ref name="93TWG">{{cite journal |title =Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements |date = 1993 |author= Barber, R. C. |author2=Greenwood, N. N. |author3=Hrynkiewicz, A. Z. |author4=Jeannin, Y. P. |author5=Lefort, M. |author6=Sakai, M. |author7=Ulehla, I. |author8=Wapstra, A. P. |author9= Wilkinson, D. H. |journal = Pure and Applied Chemistry| volume = 65 |issue = 8 |pages = 1757–1814 |doi = 10.1351/pac199365081757|s2cid = 195819585 |doi-access= free }}</ref>

In Thus1966–1969, in 1966–1969 the experiment was repeated. This time, the reaction products by gradient thermochromatography after conversion to chlorides by interaction with [[zirconium tetrachloride|ZrCl₄]]. The team identified [[spontaneous fission]] activity contained within a volatile chloride portraying eka-hafnium properties.<ref name="93TWG">{{cite journal |title =Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements |date = 1993 |author= Barber, R. C. |author2=Greenwood, N. N. |author3=Hrynkiewicz, A. Z. |author4=Jeannin, Y. P. |author5=Lefort, M. |author6=Sakai, M. |author7=Ulehla, I. |author8=Wapstra, A. P. |author9= Wilkinson, D. H. |journal = Pure and Applied Chemistry| volume = 65 |issue = 8 |pages = 1757–1814 |doi = 10.1351/pac199365081757|s2cid = 195819585 |doi-access= free }}</ref>

As a consequence of the initial competing claims of discovery, an [[element naming controversy]] arose. Since the Soviets claimed to have first detected the new element they suggested the name ''kurchatovium'' (Ku) in honor of [[Igor Kurchatov]] (1903–1960), former head of [[Soviet nuclear research]]. This name had been used in books of the [[Soviet Bloc]] as the official name of the element. The Americans, however, proposed ''rutherfordium'' (Rf) for the new element to honor [[New Zealand]] physicist [[Ernest Rutherford]], who is known as the "father" of [[nuclear physics]].<ref>{{cite web |url=http://www.rsc.org/chemistryworld/podcast/Interactive_Periodic_Table_Transcripts/Rutherfordium.asp |title=Rutherfordium |publisher=Rsc.org |access-date=2010-09-04}}</ref> In 1992, the [[International Union of Pure and Applied Chemistry|IUPAC]]/[[International Union of Pure and Applied Physics|IUPAP]] Transfermium Working Group (TWG) assessed the claims of discovery and concluded that both teams provided contemporaneous evidence to the synthesis of element 104 in 1969, and that credit should be shared between the two groups. In particular, this involved the TWG performing a new retrospective reanalysis of the Russian work in the face of the later-discovered fact that there is no 0.3-second isotope of element 104: they reinterpreted the Dubna results as having been caused by a spontaneous fission branch of ²⁵⁹Rf.<ref name="93TWG" />

The American group wrote a scathing response to the findings of the TWG, stating that they had given too much emphasis on the results from the Dubna group. In particular they pointed out that the Russian group had altered the details of their claims several times over a period of 20 years, a fact that the Russian team does not deny. They also stressed that the TWG had given too much credence to the chemistry experiments performed by the Russians, considered the TWG's retrospective treatment of the Russian work based on unpublished documents to have been "highly irregular", noted that there was no proof that ²⁵⁹Rf had a spontaneous fission branch at all<ref name=responses/> (as of 2021 there still is not),<ref>{{NUBASE2020}}</ref> and accused the TWG of not having appropriately qualified personnel on the committee. The TWG responded by saying that this was not the case and having assessed each point raised by the American group said that they found no reason to alter their conclusion regarding priority of discovery.<ref name=responses>{{cite journal |doi =10.1351/pac199365081815|title =Responses on 'Discovery of the transfermium elements' by Lawrence Berkeley Laboratory, California; Joint Institute for Nuclear Research, Dubna; and Gesellschaft fur Schwerionenforschung, Darmstadt followed by reply to responses by the Transfermium Working Group |year =1993|last1= Ghiorso|first1=A. |last2=Seaborg |first2=G. T.|last3=Organessian |first3=Yu. Ts.|last4=Zvara |first4=I.|last5=Armbruster |first5=P.|last6=Hessberger |first6=F. P.|last7=Hofmann |first7=S.|last8=Leino |first8=M.|last9=Munzenberg |first9=G.|last10=Reisdorf |first10=W.|last11=Schmidt |first11=K.-H.|journal =Pure and Applied Chemistry|volume =65|issue = 8|pages =1815–1824|doi-access=free}}</ref> The IUPAC finally used the name suggested by the American team (''rutherfordium'').<ref name="97IUPAC">{{cite journal |doi =10.1351/pac199769122471 |title =Names and symbols of transfermium elements (IUPAC Recommendations 1997) |date =1997 |journal =Pure and Applied Chemistry |volume =69 |issue = 12 |pages =2471–2474|doi-access =free }}</ref>

The International Union of Pure and Applied Chemistry ([[IUPAC]]) adopted ''unnilquadium'' (Unq) as a temporary, [[systematic element name]], derived from the Latin names for digits 1, 0, and 4. In 1994, IUPAC suggested a set of names for elements 104 through 109, in which ''dubnium'' (Db) became element 104 and ''rutherfordium'' became element 106.<ref name="1994 IUPAC">{{Cite journal|year=1994|title=Names and symbols of transfermium elements (IUPAC Recommendations 1994)|url=https://www.iupac.org/publications/pac-2007/1994/pdf/6612x2419.pdf|journal=Pure and Applied Chemistry|volume=66|issue=12|pages=2419–2421|doi=10.1351/pac199466122419|access-date=September 7, 2016|url-status=live|archive-url=https://web.archive.org/web/20170922194905/https://www.iupac.org/publications/pac-2007/1994/pdf/6612x2419.pdf|archive-date=September 22, 2017}}</ref> This recommendation was criticized by the American scientists for several reasons. Firstly, their suggestions were scrambled: the names ''rutherfordium'' and ''hahnium'', originally suggested by Berkeley for elements 104 and 105, were respectively reassigned to elements 106 and 108. Secondly, elements 104 and 105 were given names favored by JINR, despite earlier recognition of LBL as an equal co-discoverer for both of them. Thirdly and most importantly, IUPAC rejected the name ''[[seaborgium]]'' for element 106, having just approved a rule that an element could not be named after a living person, even though the IUPAC had given the LBNL team the sole credit for its discovery.<ref>{{Cite web|url=http://www2.lbl.gov/Science-Articles/Archive/seaborgium-dispute.html|title=Naming of element 106 disputed by international committee|last=Yarris|first=L.|year=1994|access-date=September 7, 2016}}</ref> In 1997, IUPAC renamed elements 104 to 109, and gave elementelements 104 and 106 the currentBerkeley nameproposals ''rutherfordium'' and ''seaborgium''. The name ''[[dubnium]]'' was given to element 105 at the same time. The 1997 names were accepted by researchers and became the standard.<ref name="97IUPAC">{{cite journal |doi =10.1351/pac199769122471 |title =Names and symbols of transfermium elements (IUPAC Recommendations 1997) |date =1997 |journal =Pure and Applied Chemistry |volume =69 |issue = 12 |pages =2471–2474|doi-access =free }}</ref>

|re=²⁵⁸Db({{SubatomicParticle|link=yes|Electron}},{{SubatomicParticle|link=yes|Electron Neutrino}})<ref name="258Db">{{cite journal | lastlast1=Heßberger | firstfirst1=F. P. | last2=Antalic | first2=S. | last3=Ackermann | first3=D. | last4=Andel | first4=B. | last5=Block | first5=M. | last6=Kalaninova | first6=Z. | last7=Kindler | first7=B. | last8=Kojouharov | first8=I. | last9=Laatiaoui | first9=M. | last10=Lommel | first10=B. | last11=Mistry | first11=A. K. | last12=Piot | first12=J. | last13=Vostinar | first13=M. | title=Investigation of electron capture decay of ²⁵⁸Db and α decay of ²⁵⁸Rf | journal=The European Physical Journal A | volume=52 | issue=11 | date=2016 | issn=1434-6001 | doi=10.1140/epja/i2016-16328-2}}</ref>

|re=²⁴⁴Pu(²²Ne,4n), </br />²⁴⁸Cm(¹⁸Ne,4n)<ref>{{cite journal | lastlast1=Somerville | firstfirst1=L. P. | last2=Nurmia | first2=M. J. | last3=Nitschke | first3=J. M. | last4=Ghiorso | first4=A. | last5=Hulet | first5=E. K. | last6=Lougheed | first6=R. W. | title=Spontaneous fission of rutherfordium isotopes | journal=Physical Review C | volume=31 | issue=5 | date=1985-05-01 | issn=0556-2813 | doi=10.1103/PhysRevC.31.1801 | pages=1801–1815| pmid=9952719 | bibcode=1985PhRvC..31.1801S }}</ref>

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|re=²⁶⁶Db({{SubatomicParticle|link=yes|Electron}},{{SubatomicParticle|link=yes|Electron Neutrino}})?<ref name="Rf266">{{cite journal |doi=10.1103/PhysRevC.76.011601 |date=2007 |issue=1 |page=011601 |volume=76 |journal=Physical Review C |title=Synthesis of the isotope 282113 in the Np237+Ca48 fusion reaction |author=Oganessian, Yu. Ts. | display-authors=1 |bibcode = 2007PhRvC..76a1601O |last2=Utyonkov |first2=V. |last3=Lobanov |first3=Yu. |last4=Abdullin |first4=F. |last5=Polyakov |first5=A. |last6=Sagaidak |first6=R. |last7=Shirokovsky |first7=I. |last8=Tsyganov |first8=Yu. |last9=Voinov |first9=A. }}</ref><ref name="iop">{{cite journal | last=Oganessian | first=Yuri | title=Nuclei in the "Island of Stability" of Superheavy Elements | journal=Journal of Physics: Conference Series | publisher=IOP Publishing | volume=337 | issue=1 | date=8 February 2012 | issn=1742-6596 | doi=10.1088/1742-6596/337/1/012005 | page=012005 | bibcode=2012JPhCS.337a2005O | doi-access=free }}</ref>

|ref=<ref name=PuCa2022"PuCa2022b">{{cite journal |title=Investigation of ⁴⁸Ca-induced reactions with ²⁴²Pu and ²³⁸U targets at the JINR Superheavy Element Factory |journal=Physical Review C |volume=106 |number=24612 |year=2022 |first1=Yu. Ts. |last1=Oganessian |first2=V. K. |last2=Utyonkov |first3=D. |last3=Ibadullayev |page=024612 |display-authors=et al. |doi= 10.1103/PhysRevC.106.024612|bibcode=2022PhRvC.106b4612O |osti=1883808 |s2cid=251759318 }}</ref>

|re=²⁷¹Sg(—,α)<ref name="springerlink1">{{cite book |author=Hofmann, S. |title=The Euroschool Lectures on Physics with Exotic Beams, Vol. III Lecture Notes in Physics |publisher=Springer |date= 2009 |pages=203–252 |doi=10.1007/978-3-540-85839-3_6 |volume=764|chapter=Superheavy Elements |series=Lecture Notes in Physics |isbn=978-3-540-85838-6 }}</ref><!---page 228--->

Out of isotopes whose half-lives are known, the lighter isotopes usually have shorter half-lives; half-lives of under 50&nbsp;μs for ²⁵³Rf and ²⁵⁴Rf were observed. ²⁵⁶Rf, ²⁵⁸Rf, ²⁶⁰Rf are more stable at around 10&nbsp;ms, ²⁵⁵Rf, ²⁵⁷Rf, ²⁵⁹Rf, and ²⁶²Rf live between 1 and 5 seconds, and ²⁶¹Rf, ²⁶⁵Rf, and ²⁶³Rf are more stable, at around 1.1, 1.5, and 10 minutes respectively. The heaviest isotopes are the most stable, with ²⁶⁷Rf having a measured half-life of about 48 minutes.<ref name=PuCa2022"PuCa2022b"/>

Very few properties of rutherfordium or its compounds have been measured; this is due to its extremely limited and expensive production<ref name="Bloomberg">{{Cite web|url=https://www.bloomberg.com/news/features/2019-08-28/making-new-elements-doesn-t-pay-just-ask-this-berkeley-scientist|title=Making New Elements Doesn't Pay. Just Ask This Berkeley Scientist|last=Subramanian|first=S.|website=[[Bloomberg Businessweek]]|access-date=2020-01-18}}</ref> and the fact that rutherfordium (and its parents) decays very quickly. A few singular chemistry-related properties have been measured, but properties of rutherfordium metal remain unknown and only predictions are available.

Initial predictions of the chemical properties of rutherfordium were based on calculations which indicated that the relativistic effects on the electron shell might be strong enough that the [[p orbital|7p orbitals]] would have a lower energy level than the [[d orbital|6d orbitals]], giving it a [[valence electron]] configuration of 6d¹ 7s² 7p¹ or even 7s² 7p², therefore making the element behave more like [[lead]] than hafnium. With better calculation methods and experimental studies of the chemical properties of rutherfordium compounds it could be shown that this does not happen and that rutherfordium instead behaves like the rest of the [[group 4 element]]s.<ref name="Haire" /><ref name="Kratz03">{{cite journal|doi=10.1351/pac200375010103 |url=http://stage.iupac.org/originalWeb/publications/pac/2003/pdf/7501x0103.pdf |title=Critical evaluation of the chemical properties of the transactinide elements (IUPAC Technical Report) |date=2003 |last1=Kratz |first1=J. V. |journal=Pure and Applied Chemistry |volume=75 |issue=1 |page=103 |s2cid=5172663 |archive-url=https://web.archive.org/web/20110726195721/http://stage.iupac.org/originalWeb/publications/pac/2003/pdf/7501x0103.pdf |archive-date=2011-07-26 }}</ref> Later it was shown in ab initio calculations with the high level of accuracy<ref name="Eliav1995">{{cite journal |last1=Eliav |first1=E. |last2=Kaldor |first2=U. |last3=Ishikawa |first3=Y. |title=Ground State Electron Configuration of Rutherfordium: Role of Dynamic Correlation |journal=Physical Review Letters |volume=74 |issue=7 |pages=1079–1082 |year=1995 |doi=10.1103/PhysRevLett.74.1079 |pmid=10058929 |bibcode=1995PhRvL..74.1079E }}</ref><ref name="Mosyagin2010">{{cite journal |last1=Mosyagin |first1=N. S. |last2=Tupitsyn |first2=I. I. |last3=Titov |first3=A. V. |title=Precision Calculation of the Low-Lying Excited States of the Rf Atom |journal=Radiochemistry |volume=52 |issue=4 |pages=394–398 |year=2010 |doi=10.1134/S1066362210040120 |bibcode=2010Radch..52..394M |s2cid=120721050 }}</ref><ref name="Dzuba2014">{{cite journal |last1=Dzuba |first1=V. A. |last2=Safronova |first2=M. S. |last3=Safronova |first3=U. I. |title=Atomic properties of superheavy elements No, Lr, and Rf |journal=Physical Review A |volume=90 |issue=1 |page=012504 |year=2014 |doi=10.1103/PhysRevA.90.012504 |arxiv=1406.0262 |bibcode=2014PhRvA..90a2504D |s2cid=74871880 }}</ref> that the Rf atom has the ground state with the 6d² 7s² valence configuration and the low-lying excited 6d¹ 7s² 7p¹ state with the excitation energy of only 0.3–0.5 eV.