Rutherfordium: Difference between revisions

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Latest revision as of 03:08, 14 August 2025

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{{distinguish|ruthenium}}

[[de:Unnilquadium]]

{{infobox rutherfordium}}

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'''Rutherfordium''' is a [[synthetic element|synthetic chemical element]]; it has [[Chemical symbol|symbol]] '''Rf''' and [[atomic number]] 104. It is named after [[physicist]] [[Ernest Rutherford]]. As a synthetic element, it is not found in nature and can only be made in a [[particle accelerator]]. It is [[radioactive]]; the most stable known [[isotope]], ²⁶⁷Rf, has a [[half-life]] of about 48 minutes.

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<th colspan="2" align=center bgcolor="#ffc0c0">'''Known properties'''</th></tr>

<tr>

<td>[[List of elements by name|Name]], [[List of elements by symbol|Symbol]], [[List of elements by number|Number]]</td><td>Rutherfordium, Rf, 104</td></tr>

<tr>

<td>[[Chemical series]] </td><td>[[Transition metal]]s</td></tr>

<tr>

<td>[[periodic table group|Group]], [[periodic table period|Period]], [[periodic table block|Block]]</td><td>[[group 4 element|4]], [[period 7 element|7]] , [[d-block|d]]</td></tr>

<tr>

<td>[[color|Appearance]] </td><td>unknown; probably metallic,<br>

silvery white or gray</td></tr>

<tr>

<td>[[Atomic weight]] </td><td>[[1 E-25 kg|<nowiki>[261]</nowiki> amu]]</td></tr>

<tr>

<td>[[Electron configuration]] </td><td>probably <nowiki>[</nowiki>[[radon|Rn]]<nowiki>]</nowiki>5[[f-orbital|f]]¹⁴ 6d² 7[[s-orbital|s]]²</td></tr>

<tr>

<td>[[electron|e^-]] 's per [[energy level]]</td><td>2,8,18,32,32,10,2</td></tr>

<tr>

<td>[[State of matter]] </td><td>Presumably a solid</td></tr>

</table>

'''Rutherfordium''' is a [[chemical element]] in the [[periodic table]] that has the symbol Rf and [[atomic number]] 104. This is a highly [[radioactive]] synthetic element whose most stable [[isotope]] has a [[half life]] of less than 70 seconds. This element therefore is not used for anything and little is known about it. Rutherfordium is the first [[transactinide element]] and is is predicted to have chemical properties similar to [[hafnium]].

In the [[periodic table]], it is a [[d-block]] element and the second of the fourth-row [[transition element]]s. It is in [[period 7]] and is a [[group 4 element]]. Chemistry experiments have confirmed that rutherfordium behaves as the heavier [[Homologous series|homolog]] to [[hafnium]] in group 4. The chemical properties of rutherfordium are characterized only partly. They compare well with the other group 4 elements, even though some calculations had indicated that the element might show significantly different properties due to [[Relativistic quantum chemistry|relativistic effects]].

== History ==

Rutherfordium (named in honor of [[Ernest Rutherford]]) was reportedly [[discovery of the chemical elements|first synthesized]] in [[1964]] at the Joint Nuclear Research Institute at [[Dubna]] ([[U.S.S.R.]]). Researches there bombarded [[plutonium]] with accelerated 113 to 115 MeV [[neon]] [[ion]]s and claimed that they detected [[nuclear fission]] tracks in a special type of glass with a [[microscope]] which indicated the presence of a new element.

In the 1960s, small amounts of rutherfordium were produced at [[Joint Institute for Nuclear Research]] in the [[Soviet Union]] and at [[Lawrence Berkeley National Laboratory]] in [[California]].<ref>{{Cite web|url=http://www.rsc.org/periodic-table/element/104/rutherfordium|title=Rutherfordium - Element information, properties and uses {{!}} Periodic Table|website=www.rsc.org|access-date=2016-12-09|archive-date=2020-05-10|archive-url=https://web.archive.org/web/20200510201424/https://www.rsc.org/periodic-table/element/104/rutherfordium|url-status=live}}</ref> Priority of discovery and hence the name of the element [[Element naming controversy|was disputed]] between Soviet and American scientists, and it was not until 1997 that the [[International Union of Pure and Applied Chemistry]] (IUPAC) established rutherfordium as the official name of the element.

In [[1969]] researchers at the [[University of California, Berkeley]] synthesized the element by subjecting [[californium]]-249 and [[carbon]]-12 to high [[energy]] collisions. The UC group also stated that they could not reproduce the earlier synthesis by Soviet scientists.

==Introduction==

This resulted in an [[element naming controversy]]; Since the Soviets claimed that it was first detected in Dubna, Dubium (Db) was suggested, as was Kurchatovium and symbol Ku for element 104, in honor of [[Igor Vasilevich Kurchatov]] ([[1903]]-[[1960]]), former Head of Soviet Nuclear Research. The Americans, however, proposed Rutherfordium (symbol Rf) for the new element to honor Ernest R. Rutherford a noted [[New Zealand]] nuclear physicist. The International Union of Pure and Applied Physics ([[IUPAC]]) adopted Unnilquadium (symbol Unq) as a temporary name for this element. However in [[1997]] they resolved the dispute and adopted the current name.

{{Excerpt|Superheavy element|Introduction|subsections=yes}}

==History==

== External links ==

*[http://www.webelements.com/webelements/elements/text/Rf/index.html WebElements.com - Rutherfordium]

===Discovery===

*[http://environmentalchemistry.com/yogi/periodic/Rf.html EnvironmentalChemistry.com - Rutherfordium]

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 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"/>

:{{nuclide|plutonium|242}} + {{nuclide|neon|22}} → ^264−''x''104 → ^264−''x''104Cl₄

The researchers considered the results to support the 0.3&nbsp;second half-life. Although it is now known that there is no isotope of element 104 with such a half-life, the chemistry does fit that of element 104, as chloride volatility is much greater in group 4 than in group 3 (or the actinides).<ref name=93TWG/>

In 1969, researchers at [[University of California, Berkeley]] conclusively synthesized the element by bombarding a [[californium]]-249 target with [[carbon-12]] ions and measured the alpha decay of ²⁵⁷104, correlated with the daughter decay of [[nobelium]]-253:<ref name="69Gh01">{{cite journal |doi = 10.1103/PhysRevLett.22.1317 |title = Positive Identification of Two Alpha-Particle-Emitting Isotopes of Element 104 |date = 1969 |last1 = Ghiorso |first1 = A. |last2 = Nurmia |first2 = M. |journal = Physical Review Letters |volume = 22 |issue = 24 |pages = 1317–1320 |bibcode = 1969PhRvL..22.1317G |last3 = Harris |first3 = J. |last4 = Eskola |first4 = K. |last5 = Eskola |first5 = P. |url = https://cloudfront.escholarship.org/dist/prd/content/qt3fm666nq/qt3fm666nq.pdf |access-date = 2019-04-05 |archive-date = 2018-07-22 |archive-url = https://web.archive.org/web/20180722035431/https://cloudfront.escholarship.org/dist/prd/content/qt3fm666nq/qt3fm666nq.pdf |url-status = live }}</ref>

:{{nuclide|californium|249}} + {{nuclide|carbon|12}} → ²⁵⁷104 + 4 {{SubatomicParticle|neutron}}

They were unable to confirm the 0.3-second half-life for ²⁶⁰104, and instead found a 10–30 millisecond half-life for this isotope, agreeing with the modern value of 21 milliseconds. In 1970, the American team chemically identified element 104 using the ion-exchange separation method, proving it to be a group 4 element and the heavier homologue of hafnium.<ref name=responses/>

The American synthesis was independently confirmed in 1973 and secured the identification of rutherfordium as the parent by the observation of [[K-alpha]] [[X-rays]] in the elemental signature of the ²⁵⁷104 decay product, nobelium-253.<ref name="73Be01">{{cite journal |doi =10.1103/PhysRevLett.31.647 |title =X-Ray Identification of Element 104 |date =1973 |author =Bemis, C. E. |journal =Physical Review Letters |volume =31 |issue =10 |pages =647–650 |bibcode=1973PhRvL..31..647B |last2 =Silva |first2 =R. |last3 =Hensley |first3 =D. |last4 =Keller |first4 =O. |last5 =Tarrant |first5 =J. |last6 =Hunt |first6 =L. |last7 =Dittner |first7 =P. |last8 =Hahn |first8 =R. |last9 =Goodman |first9 =C. }}</ref>

===Naming controversy===

{{Main|Transfermium Wars}}

[[File:Ernest Rutherford2.jpg|thumb|left|upright|Element 104 was eventually named after [[Ernest Rutherford]]]]

[[File:Igor Kurchatov 001.png|thumb|left|upright|Igor Kurchatov]]

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 |archive-date=2011-04-08 |archive-url=https://web.archive.org/web/20110408194724/http://www.rsc.org/chemistryworld/podcast/Interactive_Periodic_Table_Transcripts/Rutherfordium.asp |url-status=live }}</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 ²⁵⁹104.<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 ²⁵⁹104 had a spontaneous fission branch at all<ref name=responses/> (as of 2021 there still is not),{{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 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|archive-date=July 1, 2016|archive-url=https://web.archive.org/web/20160701203756/http://www2.lbl.gov/Science-Articles/Archive/seaborgium-dispute.html|url-status=live}}</ref> In 1997, IUPAC renamed elements 104 to 109, and gave elements 104 and 106 the Berkeley proposals ''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>

{{clear}}

==Isotopes==

{{Main|Isotopes of rutherfordium}}

Rutherfordium has no stable or naturally occurring isotopes. Several radioactive isotopes have been synthesized in the laboratory, either by fusing two atoms or by observing the decay of heavier elements. Seventeen different isotopes have been reported with atomic masses from 252 to 270 (with the exceptions of 264 and 269). Most of these decay predominantly through spontaneous fission, particularly isotopes with [[even and odd atomic nuclei|even neutron numbers]], while some of the lighter isotopes with odd neutron numbers also have significant alpha decay branches.<ref name="nuclidetable" /><ref name="isotopes">{{cite web | title=Six New Isotopes of the Superheavy Elements Discovered | website=Berkeley Lab News Center | date=26 October 2010 | url=https://newscenter.lbl.gov/2010/10/26/six-new-isotopes/ | access-date=5 April 2019}}</ref>

===Stability and half-lives===

Out of isotopes whose half-lives are known, the lighter isotopes usually have shorter half-lives. The three lightest known isotopes have half-lives of under 50&nbsp;μs, with the lightest reported isotope ²⁵²Rf having a half-life shorter than one microsecond.<ref name=252Rf>{{cite journal |first1=J. |last1=Khuyagbaatar |first2=P. |last2=Mosat |first3=J. |last3=Ballof |first4=R. A. |last4=Cantemir |first5=Ch. E. |last5=Düllmann |first6=K. |last6=Hermainski |first7=F. P. |last7=Heßberger |first8=E. |last8=Jäger |first9=B. |last9=Kindler |first10=J. |last10=Krier |first11=N. |last11=Kurz |first12=S. |last12=Löchner |first13=B. |last13=Lommel |first14=B. |last14=Schausten |first15=Y. |last15=Wei |first16=P. |last16=Wieczorek |first17=A. |last17=Yakushev |display-authors=3 |title=Stepping into the sea of instability: The new sub-𝜇s superheavy nucleus ²⁵²Rf |journal=Physical Review Letters |date=2025 |volume=134 |number=22501 |page=022501 |doi=10.1103/PhysRevLett.134.022501|pmid=39913845 |arxiv=2501.08955 }}</ref><ref name="253Rf-2022">{{cite journal |last1=Lopez-Martens |first1=A. |last2=Hauschild |first2=K. |last3=Svirikhin |first3=A. I. |last4=Asfari |first4=Z. |last5=Chelnokov |first5=M. L. |last6=Chepigin |first6=V. I. |last7=Dorvaux |first7=O. |last8=Forge |first8=M. |last9=Gall |first9=B. |last10=Isaev |first10=A. V. |last11=Izosimov |first11=I. N. |last12=Kessaci |first12=K. |last13=Kuznetsova |first13=A. A. |last14=Malyshev |first14=O. N. |last15=Mukhin |first15=R. S. |last16=Popeko |first16=A. G. |last17=Popov |first17=Yu. A. |last18=Sailaubekov |first18=B. |last19=Sokol |first19=E. A. |last20=Tezekbayeva |first20=M. S. |last21=Yeremin |first21=A. V. |display-authors=3 |title=Fission properties of Rf 253 and the stability of neutron-deficient Rf isotopes |journal=Physical Review C |date=22 February 2022 |volume=105 |issue=2 |article-number=L021306 |doi=10.1103/PhysRevC.105.L021306 |url=https://journals.aps.org/prc/pdf/10.1103/PhysRevC.105.L021306 |access-date=16 June 2023 |language=en |issn=2469-9985|arxiv=2202.11802 |s2cid=247072308 }}</ref> The isotopes 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 most stable known isotope, ²⁶⁷Rf, is one of the heaviest, and has a half-life of about 48 minutes.<ref name="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> Rutherfordium isotopes with an odd neutron number tend to have longer half-lives than their even–even neighbors because the odd neutron provides additional hindrance against spontaneous fission.

The lightest isotopes were synthesized by direct fusion between two lighter nuclei and as decay products. The heaviest isotope produced by direct fusion is ²⁶²Rf; heavier isotopes have only been observed as decay products of elements with larger atomic numbers. The heavy isotopes ²⁶⁶Rf and ²⁶⁸Rf have also been reported as [[electron capture]] daughters of the [[dubnium]] isotopes ²⁶⁶Db and ²⁶⁸Db, but have short half-lives to [[spontaneous fission]]. It seems likely that the same is true for ²⁷⁰Rf, a possible daughter of ²⁷⁰Db.<ref name="270Rf">{{cite book|last=Stock|first=Reinhard|title=Encyclopedia of Nuclear Physics and its Applications|url=https://books.google.com/books?id=zVrdAAAAQBAJ&pg=PT305|date=13 September 2013|publisher=John Wiley & Sons|isbn=978-3-527-64926-6|page=305|oclc=867630862}}</ref> These three isotopes remain unconfirmed.

In 1999, American scientists at the University of California, Berkeley, announced that they had succeeded in synthesizing three atoms of ²⁹³Og.<ref>{{cite journal |last=Ninov |first=Viktor |display-authors=etal |title=Observation of Superheavy Nuclei Produced in the Reaction of {{SimpleNuclide|Krypton|86}} with {{SimpleNuclide|Lead|208}} |journal=[[Physical Review Letters]] |volume=83 |issue=6 |pages=1104–1107 |date=1999 |doi=10.1103/PhysRevLett.83.1104 |bibcode=1999PhRvL..83.1104N |url=https://zenodo.org/record/1233919 |access-date=2018-11-04 |archive-date=2023-07-18 |archive-url=https://web.archive.org/web/20230718161424/https://zenodo.org/record/1233919 |url-status=live }}</ref> These parent nuclei were reported to have successively emitted seven alpha particles to form ²⁶⁵Rf nuclei, but their claim was retracted in 2001.<ref>{{cite web | title=Results of Element 118 Experiment Retracted | website=Berkeley Lab Research News | date=2001-07-21 | url=http://enews.lbl.gov/Science-Articles/Archive/118-retraction.html | archive-url=https://web.archive.org/web/20080129191344/http://enews.lbl.gov/Science-Articles/Archive/118-retraction.html | archive-date=29 January 2008 | access-date=5 April 2019 |df=dmy-all}}</ref> This isotope was later discovered in 2010 as the final product in the decay chain of ²⁸⁵Fl.<ref name="PuCa2017" /><ref name="10El">{{cite journal|last1=Ellison|first1=P.|last2=Gregorich|first2=K.|last3=Berryman|first3=J.|last4=Bleuel|first4=D.|last5=Clark|first5=R.|last6=Dragojević|first6=I.|last7=Dvorak|first7=J.|last8=Fallon|first8=P.|last9=Fineman-Sotomayor|first9=C.|display-authors=etal|title=New Superheavy Element Isotopes: ²⁴²Pu(⁴⁸Ca,5n)²⁸⁵114|journal=Physical Review Letters|volume=105|year=2010|doi=10.1103/PhysRevLett.105.182701|bibcode=2010PhRvL.105r2701E|pmid=21231101|issue=18|page=182701|osti=1000353 |url=https://digital.library.unt.edu/ark:/67531/metadc831769/|access-date=2019-07-14|archive-date=2019-07-02|archive-url=https://web.archive.org/web/20190702153317/https://digital.library.unt.edu/ark:/67531/metadc831769/|url-status=live}}</ref>

==Predicted properties==

<!---http://www.rsc.org/chemistryworld/podcast/Interactive_Periodic_Table_Transcripts/Rutherfordium.asp--->

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|archive-date=2020-11-14|archive-url=https://archive.today/20201114183428/https://www.bloomberg.com/news/features/2019-08-28/making-new-elements-doesn-t-pay-just-ask-this-berkeley-scientist|url-status=live}}</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.

===Chemical===

Rutherfordium is the first [[transactinide element]] and the second member of the 6d series of transition metals. Calculations on its [[ionization potential]]s, [[atomic radius]], as well as radii, orbital energies, and ground levels of its ionized states are similar to that of [[hafnium]] and very different from that of [[lead]]. Therefore, it was concluded that rutherfordium's basic properties will resemble those of other [[group 4 element]]s, below [[titanium]], [[zirconium]], and hafnium.<ref name="Rf263">{{cite journal |url=http://www.ulrich-rieth.de/publikationen/RCA0301_059.PDF |title=An EC-branch in the decay of 27-s²⁶³Db: Evidence for the new isotope ²⁶³Rf |author=Kratz, J. V. |journal=Radiochim. Acta |volume=91 |issue=1–2003 |pages=59–62 |date=2003 |doi=10.1524/ract.91.1.59.19010 |last2=Nähler |first2=A. |last3=Rieth |first3=U. |last4=Kronenberg |first4=A. |last5=Kuczewski |first5=B. |last6=Strub |first6=E. |last7=Brüchle |first7=W. |last8=Schädel |first8=M. |last9=Schausten |first9=B. |last10=Türler |first10=A. |last11=Gäggeler |first11=H. W. |last12=Jost |first12=D. T. |last13=Gregorich |first13=K. E. |last14=Nitsche |first14=H. |last15=Laue |first15=C. |last16=Sudowe |first16=R. |last17=Wilk |first17=P. A. |s2cid=96560109 |display-authors=8 |archive-url=https://web.archive.org/web/20090225154858/http://www.ulrich-rieth.de/publikationen/RCA0301_059.PDF |archive-date=2009-02-25 }}</ref><ref name="Kratz03" /> Some of its properties were determined by gas-phase experiments and aqueous chemistry. The oxidation state +4 is the only stable state for the latter two elements and therefore rutherfordium should also exhibit a stable +4 state.<ref name="Kratz03" /> In addition, rutherfordium is also expected to be able to form a less stable +3 state.<ref name="Haire" /> The [[standard reduction potential]] of the Rf⁴⁺/Rf couple is predicted to be higher than −1.7&nbsp;V.{{Fricke1975}}

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.

In an analogous manner to zirconium and hafnium, rutherfordium is projected to form a very stable, [[refractory]] oxide, RfO₂. It reacts with halogens to form tetrahalides, RfX₄, which hydrolyze on contact with water to form oxyhalides RfOX₂. The tetrahalides are volatile solids existing as monomeric tetrahedral molecules in the vapor phase.<ref name="Kratz03" />

In the aqueous phase, the Rf⁴⁺ ion hydrolyzes less than titanium(IV) and to a similar extent as zirconium and hafnium, thus resulting in the RfO²⁺ ion. Treatment of the halides with halide ions promotes the formation of complex ions. The use of chloride and bromide ions produces the hexahalide complexes {{chem|RfCl|6|2-}} and {{chem|RfBr|6|2-}}. For the fluoride complexes, zirconium and hafnium tend to form hepta- and octa- complexes. Thus, for the larger rutherfordium ion, the complexes {{chem|RfF|6|2-}}, {{chem|RfF|7|3-}} and {{chem|RfF|8|4-}} are possible.<ref name="Kratz03" />

===Physical and atomic===

<section begin=properties />

Rutherfordium is expected to be a solid under normal conditions and have a [[hexagonal close-packed]] crystal structure (^''c''/_''a''&nbsp;=&nbsp;1.61), similar to its lighter [[congener (chemistry)|congener]] hafnium.<ref name="hcp" /> It should be a metal with [[density]] ~17&nbsp;g/cm³.<ref name=density>{{cite journal |last1=Gyanchandani |first1=Jyoti |last2=Sikka |first2=S. K. |title=Physical properties of the 6 d -series elements from density functional theory: Close similarity to lighter transition metals |journal=Physical Review B |date=10 May 2011 |volume=83 |issue=17 |page=172101 |doi=10.1103/PhysRevB.83.172101 |bibcode=2011PhRvB..83q2101G }}</ref><ref name=kratz>{{cite book |last1=Kratz |last2=Lieser |title=Nuclear and Radiochemistry: Fundamentals and Applications |date=2013 |page=631 |edition=3rd}}</ref> The atomic radius of rutherfordium is expected to be ~150&nbsp;[[picometer|pm]]. Due to relativistic stabilization of the 7s orbital and destabilization of the 6d orbital, Rf⁺ and Rf²⁺ ions are predicted to give up 6d electrons instead of 7s electrons, which is the opposite of the behavior of its lighter homologs.<ref name="Haire" /> When under high pressure (variously calculated as 72 or ~50 [[gigapascal|GPa]]), rutherfordium is expected to transition to [[body-centered cubic]] crystal structure; hafnium transforms to this structure at 71±1&nbsp;GPa, but has an intermediate ω structure that it transforms to at 38±8&nbsp;GPa that should be lacking for rutherfordium.<ref>{{cite journal | last1=Gyanchandani | first1=Jyoti | last2=Sikka | first2=S.K. | title=Structural properties of rutherfordium: An ab-initio study | journal=Physics Letters A | volume=376 | issue=4 | date=2012 | doi=10.1016/j.physleta.2011.11.053 | pages=620–625 |arxiv=1106.3146| bibcode=2012PhLA..376..620G }}</ref><section end=properties />

==Experimental chemistry==

===Gas phase===

[[File:RfCl4.png|class=skin-invert-image|thumb|upright=0.5|The tetrahedral structure of the RfCl₄ molecule]]

Early work on the study of the chemistry of rutherfordium focused on gas thermochromatography and measurement of relative deposition temperature adsorption curves. The initial work was carried out at Dubna in an attempt to reaffirm their discovery of the element. Recent work is more reliable regarding the identification of the parent rutherfordium radioisotopes. The isotope ^261mRf has been used for these studies,<ref name="Kratz03" /> though the long-lived isotope ²⁶⁷Rf (produced in the decay chain of ²⁹¹Lv, ²⁸⁷Fl, and ²⁸³Cn) may be advantageous for future experiments.<ref name="Moody">{{cite book |chapter=Synthesis of Superheavy Elements |last1=Moody |first1=Ken |editor1-first=Matthias |editor1-last=Schädel |editor2-first=Dawn |editor2-last=Shaughnessy |title=The Chemistry of Superheavy Elements |publisher=Springer Science & Business Media |edition=2nd |pages=24–8 |isbn=978-3-642-37466-1|date=2013-11-30 }}</ref> The experiments relied on the expectation that rutherfordium would be a 6d element in group 4 and should therefore form a volatile molecular tetrachloride, that would be tetrahedral in shape.<ref name="Kratz03" /><ref name="autogenerated1">{{cite journal |last1=Oganessian |first1=Yury Ts |last2=Dmitriev |first2=Sergey N. |title=Superheavy elements in D I Mendeleev's Periodic Table |journal=Russian Chemical Reviews |volume=78 |issue=12 |page=1077 |date=2009 |doi=10.1070/RC2009v078n12ABEH004096 |bibcode = 2009RuCRv..78.1077O |s2cid=250848732 }}</ref><ref>{{cite journal |doi = 10.1016/S0925-8388(98)00072-3 |title =Evidence for relativistic effects in the chemistry of element 104 |first9 = D. |last10 =Timokhin |first10 = S. N. |last11 =Yakushev |first11 = A. B. |last12 =Zvara |first12 =I. |last9 = Piguet |first8 = V. Ya. |last8 = Lebedev |first7 = D. T. |last7 = Jost |first6 = S. |last6 = Hübener |first5 = M. |last5 = Grantz |first4 = H. W. |last4 = Gäggeler |first3 = B. |last3 = Eichler |first2 = G. V. |date = 1998 |last2 = Buklanov |last1 = Türler| first1 = A. | journal = Journal of Alloys and Compounds |volume = 271–273 |page = 287| display-authors=8}}</ref> Rutherfordium(IV) chloride is more volatile than its lighter homologue [[hafnium(IV) chloride]] (HfCl₄) because its bonds are more [[covalent bond|covalent]].<ref name="Haire" />

A series of experiments confirmed that rutherfordium behaves as a typical member of group 4, forming a tetravalent chloride (RfCl₄) and bromide (RfBr₄) as well as an oxychloride (RfOCl₂). A decreased volatility was observed for {{chem|RfCl|4}} when [[potassium chloride]] is provided as the solid phase instead of gas, highly indicative of the formation of nonvolatile {{chem|K|2|RfCl|6}} mixed salt.<ref name="Rf263" /><ref name="Kratz03" /><ref>{{cite web|url=http://lch.web.psi.ch/files/lectures/TexasA&M/TexasA&M.pdf |title=Lecture Course Texas A&M: Gas Phase Chemistry of Superheavy Elements |date=2007-11-05 |access-date=2010-03-30 |first=Heinz W. |last=Gäggeler |archive-url=https://web.archive.org/web/20120220090755/http://lch.web.psi.ch/files/lectures/TexasA%26M/TexasA%26M.pdf |archive-date=2012-02-20 }}</ref>

===Aqueous phase===

Rutherfordium is expected to have the electron configuration [Rn]5f¹⁴ 6d² 7s² and therefore behave as the heavier homologue of [[hafnium]] in group 4 of the periodic table. It should therefore readily form a hydrated Rf⁴⁺ ion in strong acid solution and should readily form complexes in [[hydrochloric acid]], [[hydrobromic acid|hydrobromic]] or [[hydrofluoric acid]] solutions.<ref name="Kratz03" />

The most conclusive aqueous chemistry studies of rutherfordium have been performed by the Japanese team at [[Japan Atomic Energy Research Institute]] using the isotope ^261mRf. Extraction experiments from hydrochloric acid solutions using isotopes of rutherfordium, hafnium, zirconium, as well as the pseudo-group 4 element [[thorium]] have proved a non-actinide behavior for rutherfordium. A comparison with its lighter homologues placed rutherfordium firmly in group 4 and indicated the formation of a hexachlororutherfordate complex in chloride solutions, in a manner similar to hafnium and zirconium.<ref name="Kratz03" /><ref>{{cite journal | doi=10.1524/ract.2005.93.9-10.519 | title=Chemical studies on rutherfordium (Rf) at JAERI | date=2005 | last1=Nagame | first1=Y. | journal=Radiochimica Acta | volume=93 | issue=9–10_2005 | page=519 | url=http://wwwsoc.nii.ac.jp/jnrs/paper/JN62/jn6202.pdf | last2=Tsukada | first2=K. | last3=Asai | first3=M. | last4=Toyoshima | first4=A. | last5=Akiyama | first5=K. | last6=Ishii | first6=Y. | last7=Kaneko-Sato | first7=T. | last8=Hirata | first8=M. | last9=Nishinaka | first9=I. | last10=Ichikawa | first10=S. | last11=Haba | first11=H. | last12=Enomoto | first12=Shuichi | s2cid=96299943 | display-authors=1 | archive-url=https://web.archive.org/web/20080528125634/http://wwwsoc.nii.ac.jp/jnrs/paper/JN62/jn6202.pdf | archive-date=2008-05-28 }}</ref>

:{{chem|261m|Rf|4+}} + 6 {{chem|Cl|-}} → {{chem|[|^261mRfCl|6|]|2-}}

Very similar results were observed in hydrofluoric acid solutions. Differences in the extraction curves were interpreted as a weaker affinity for fluoride ion and the formation of the hexafluororutherfordate ion, whereas hafnium and zirconium ions complex seven or eight fluoride ions at the concentrations used:<ref name="Kratz03" />

:{{chem|261m|Rf|4+}} + 6 {{chem|F|-}} → {{chem|[|^261mRfF|6|]|2-}}

Experiments performed in mixed sulfuric and nitric acid solutions shows that rutherfordium has a much weaker affinity towards forming sulfate complexes than hafnium. This result is in agreement with predictions, which expect rutherfordium complexes to be less stable than those of zirconium and hafnium because of a smaller ionic contribution to the bonding. This arises because rutherfordium has a larger ionic radius (76&nbsp;pm) than zirconium (71&nbsp;pm) and hafnium (72&nbsp;pm), and also because of relativistic stabilisation of the 7s orbital and destabilisation and spin–orbit splitting of the 6d orbitals.<ref>{{cite journal |last1=Li |first1=Z. J. |last2=Toyoshima |first2=A. |first3=M. |last3=Asai |first4=K. |last4=Tsukada |first5=T. K. |last5=Sato |first6=N. |last6=Sato |first7=T. |last7=Kikuchi |first8=Y. |last8=Nagame |first9=M. |last9=Schädel |first10=V. |last10=Pershina |first11=X. H. |last11=Liang |first12=Y. |last12=Kasamatsu |first13=Y. |last13=Komori |first14=K. |last14=Ooe |first15=A. |last15=Shinohara |first16=S. |last16=Goto |first17=H. |last17=Murayama |first18=M. |last18=Murakami |first19=H. |last19=Kudo |first20=H. |last20=Haba |first21=Y. |last21=Takeda |first22=M. |last22=Nishikawa |first23=A. |last23=Yokoyama |first24=S. |last24=Ikarashi |first25=K. |last25=Sueki |first26=K. |last26=Akiyama |first27=J. V. |last27=Kratz |display-authors=3 |date=2012 |title=Sulfate complexation of element 104, Rf, in H₂SO₄/HNO₃ mixed solution |url= |journal=Radiochimica Acta |volume=100 |issue=3 |pages=157–164 |doi=10.1524/ract.2012.1898 |s2cid=100852185 }}</ref>

Coprecipitation experiments performed in 2021 studied rutherfordium's behaviour in basic solution containing [[ammonia]] or [[sodium hydroxide]], using zirconium, hafnium, and thorium as comparisons. It was found that rutherfordium does not strongly coordinate with ammonia and instead coprecipitates out as a hydroxide, which is probably Rf(OH)₄.<ref>{{cite journal |last1=Kasamatsu |first1=Yoshitaka |last2=Toyomura |first2=Keigo |first3=Hiromitsu |last3=Haba |first4=Takuya |last4=Yokokita |first5=Yudai |last5=Shigekawa |first6=Aiko |last6=Kino |first7=Yuki |last7=Yasuda |first8=Yukiko |last8=Komori |first9=Jumpei |last9=Kanaya |first10=Minghui |last10=Huang |first11=Masashi |last11=Murakami |first12=Hidetoshi |last12=Kikunaga |first13=Eisuke |last13=Watanabe |first14=Takashi |last14=Yoshimura |first15=Kosuke |last15=Morita |first16=Toshiaki |last16=Mitsugashira |first17=Koichi |last17=Takamiya |first18=Tsutomu |last18=Ohtsuki |first19=Atsushi |last19=Shinohara |display-authors=3 |date=2021 |title=Co-precipitation behaviour of single atoms of rutherfordium in basic solutions |url= |journal=Nature Chemistry |volume=13 |issue= 3|pages=226–230 |doi=10.1038/s41557-020-00634-6 |pmid=33589784 |bibcode=2021NatCh..13..226K |s2cid=231931604 }}</ref>

==Notes==

{{Notelist}}

==References==

{{Reflist|30em}}

== Bibliography ==

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|bibcode=2017ChPhC..41c0001A }}<!--for consistency and specific pages, do not replace with {{NUBASE2016}}-->

* {{cite book|last=Beiser|first=A.|title=Concepts of modern physics|date=2003|publisher=McGraw-Hill|isbn=978-0-07-244848-1|edition=6th|oclc=48965418}}

* {{cite book |last1=Hoffman |first1=D. C. |author-link=Darleane C. Hoffman |last2=Ghiorso |first2=A. |author-link2=Albert Ghiorso |last3=Seaborg |first3=G. T. |title=The Transuranium People: The Inside Story |year=2000 |publisher=[[World Scientific]] |isbn=978-1-78-326244-1 }}

* {{cite book |last=Kragh |first=H. |author-link=Helge Kragh |date=2018 |title=From Transuranic to Superheavy Elements: A Story of Dispute and Creation |publisher=[[Springer Science+Business Media|Springer]] |isbn=978-3-319-75813-8 }}

* {{cite journal|last1=Zagrebaev|first1=V.|last2=Karpov|first2=A.|last3=Greiner|first3=W.|date=2013|title=Future of superheavy element research: Which nuclei could be synthesized within the next few years?|journal=[[Journal of Physics: Conference Series]]|volume=420|issue=1|page=012001|doi=10.1088/1742-6596/420/1/012001|arxiv=1207.5700|bibcode=2013JPhCS.420a2001Z|s2cid=55434734|issn=1742-6588}}

==External links==

*{{Commons category-inline}}

* [http://www.periodicvideos.com/videos/104.htm Rutherfordium] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)

* [http://www.webelements.com/webelements/elements/text/Rf/index.html WebElements.com – Rutherfordium]

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