Copernicium: Difference between revisions

Latest revision as of 19:49, 6 November 2025

Template:Good article Template:Infobox copernicium Template:Use dmy dates Copernicium is a synthetic chemical element; it has symbol Cn and atomic number 112. Its known isotopes are extremely radioactive, and have only been created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 30 seconds. Copernicium was first created in February 1996 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany. It was named after the astronomer Nicolaus Copernicus on his 537th anniversary.

In the periodic table of the elements, copernicium is a d-block transactinide element and a group 12 element. During reactions with gold, it has been shown^[1] to be an extremely volatile element, so much so that it is possibly a gas or a volatile liquid at standard temperature and pressure.

Copernicium is calculated to have several properties that differ from its lighter homologues in group 12, zinc, cadmium and mercury; due to relativistic effects, it may give up its 6d electrons instead of its 7s ones, and it may have more similarities to the noble gases such as radon rather than its group 12 homologues. Calculations indicate that copernicium may show the oxidation state +4, while mercury shows it in only one compound of disputed existence and zinc and cadmium do not show it at all. It has also been predicted to be more difficult to oxidize copernicium from its neutral state than the other group 12 elements. Predictions vary on whether solid copernicium would be a metal, semiconductor, or insulator. Copernicium is one of the heaviest elements whose chemical properties have been experimentally investigated.

Introduction

Template:Excerpt

History

Discovery

Copernicium was first created on 9 February 1996, at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany, by Sigurd Hofmann, Victor Ninov et al.^[2] This element was created by firing accelerated zinc-70 nuclei at a target made of lead-208 nuclei in a heavy ion accelerator. A single atom of copernicium was produced with a mass number of 277. (A second was originally reported, but was found to have been based on data fabricated by Ninov, and was thus retracted.)^[2]

Template:SuPb + Template:SuZn → Template:SuCn* → Template:SuCn + Template:Sun

In May 2000, the GSI successfully repeated the experiment to synthesize a further atom of copernicium-277.^[3] This reaction was repeated at RIKEN using the Search for a Super-Heavy Element Using a Gas-Filled Recoil Separator set-up in 2004 and 2013 to synthesize three further atoms and confirm the decay data reported by the GSI team.^[4]^[5] This reaction had also previously been tried in 1971 at the Joint Institute for Nuclear Research in Dubna, Russia, to aim for ²⁷⁶Cn (produced in the 2n channel), but without success.^[6]

The IUPAC/IUPAP Joint Working Party (JWP) assessed the claim of copernicium's discovery by the GSI team in 2001^[7] and 2003.^[8] In both cases, they found that there was insufficient evidence to support their claim. This was primarily related to the contradicting decay data for the known nuclide rutherfordium-261. However, between 2001 and 2005, the GSI team studied the reaction ²⁴⁸Cm(²⁶Mg,5n)²⁶⁹Hs, and were able to confirm the decay data for hassium-269 and rutherfordium-261. It was found that the existing data on rutherfordium-261 was for an isomer,^[9] now designated rutherfordium-261m.

In May 2009, the JWP reported on the claims of discovery of element 112 again and officially recognized the GSI team as the discoverers of element 112.^[10] This decision was based on the confirmation of the decay properties of daughter nuclei as well as the confirmatory experiments at RIKEN.^[11]

Work had also been done at the Joint Institute for Nuclear Research in Dubna, Russia from 1998 to synthesize the heavier isotope ²⁸³Cn in the hot fusion reaction ²³⁸U(⁴⁸Ca,3n)²⁸³Cn; most observed atoms of ²⁸³Cn decayed by spontaneous fission, although an alpha decay branch to ²⁷⁹Ds was detected. While initial experiments aimed to assign the produced nuclide with its observed long half-life of 3 minutes based on its chemical behaviour, this was found to be not mercury-like as would have been expected (copernicium being under mercury in the periodic table),^[11] and indeed now it appears that the long-lived activity might not have been from ²⁸³Cn at all, but its electron capture daughter ²⁸³Rg instead, with a shorter 4-second half-life associated with ²⁸³Cn. (Another possibility is assignment to a metastable isomeric state, ^283mCn.)^[12] While later cross-bombardments in the ²⁴²Pu+⁴⁸Ca and ²⁴⁵Cm+⁴⁸Ca reactions succeeded in confirming the properties of ²⁸³Cn and its parents ²⁸⁷Fl and ²⁹¹Lv, and played a major role in the acceptance of the discoveries of flerovium and livermorium (elements 114 and 116) by the JWP in 2011, this work originated subsequent to the GSI's work on ²⁷⁷Cn and priority was assigned to the GSI.^[11]

Naming

a painted portrait of Copernicus

Nicolaus Copernicus, who formulated a heliocentric model with the planets orbiting around the Sun, replacing Ptolemy's earlier geocentric model

Using Mendeleev's nomenclature for unnamed and undiscovered elements, copernicium should be known as eka-mercury. In 1979, IUPAC published recommendations according to which the element was to be called ununbium (with the corresponding symbol of Uub),^[13] a systematic element name as a placeholder, until the element was discovered (and the discovery then confirmed) and a permanent name was decided on. Although widely used in the chemical community on all levels, from chemistry classrooms to advanced textbooks, the recommendations were mostly ignored among scientists in the field, who either called it "element 112", with the symbol of E112, (112), or even simply 112.^[14]

After acknowledging the GSI team's discovery, the IUPAC asked them to suggest a permanent name for element 112.^[11]^[15] On 14 July 2009, they proposed copernicium with the element symbol Cp, after Nicolaus Copernicus "to honor an outstanding scientist, who changed our view of the world".^[16]

During the standard six-month discussion period among the scientific community about the naming,^[17]^[18] it was pointed out that the symbol Cp was previously associated with the name cassiopeium (cassiopium), now known as lutetium (Lu).^[19]^[20] Moreover, Cp is frequently used today to mean the cyclopentadienyl ligand (C₅H₅).^[21] Primarily because cassiopeium (Cp) was (until 1949) accepted by IUPAC as an alternative allowed name for lutetium,^[22] the IUPAC disallowed the use of Cp as a future symbol, prompting the GSI team to put forward the symbol Cn as an alternative. On 19 February 2010, the 537th anniversary of Copernicus' birth, IUPAC officially accepted the proposed name and symbol.^[17]^[23]

Isotopes

Script error: No such module "Labelled list hatnote". Template:Isotopes summary Copernicium 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. Eight different isotopes have been reported with mass numbers 277 and 280–286, and one unconfirmed metastable isomer in ²⁸⁵Cn has been reported.^[24] Most of these decay predominantly through alpha decay, but some undergo spontaneous fission, and copernicium-283 may have an electron capture branch.^[25]

The isotope copernicium-283 was instrumental in the confirmation of the discoveries of the elements flerovium and livermorium.^[26]

Half-lives

All confirmed copernicium isotopes are extremely unstable and radioactive; in general, heavier isotopes are more stable than the lighter, and isotopes with an odd neutron number have relatively longer half-lives due to additional hindrance against spontaneous fission. The most stable known isotope, ²⁸⁵Cn, has a half-life of 30 seconds; ²⁸³Cn has a half-life of 4 seconds, and the unconfirmed ^285mCn and ²⁸⁶Cn have half-lives of about 15 and 8.45 seconds respectively. Other isotopes have half-lives shorter than one second. ²⁸¹Cn and ²⁸⁴Cn both have half-lives on the order of 0.1 seconds, and the remaining isotopes have half-lives shorter than one millisecond.^[25] It is predicted that the heavy isotopes ²⁹¹Cn and ²⁹³Cn may have half-lives longer than a few decades, for they are predicted to lie near the center of the theoretical island of stability, and may have been produced in the r-process and be detectable in cosmic rays, though they would be about 10⁻¹² times as abundant as lead.Template:Sfn

The lightest isotopes of copernicium have been synthesized by direct fusion between two lighter nuclei and as decay products (except for ²⁷⁷Cn, which is not known to be a decay product), while the heavier isotopes are only known to be produced by decay of heavier nuclei. The heaviest isotope produced by direct fusion is ²⁸³Cn; the three heavier isotopes, ²⁸⁴Cn, ²⁸⁵Cn, and ²⁸⁶Cn, have only been observed as decay products of elements with larger atomic numbers.^[25]

In 1999, American scientists at the University of California, Berkeley, announced that they had succeeded in synthesizing three atoms of ²⁹³Og.^[27] These parent nuclei were reported to have successively emitted three alpha particles to form copernicium-281 nuclei, which were claimed to have undergone alpha decay, emitting alpha particles with decay energy 10.68 MeV and half-life 0.90 ms, but their claim was retracted in 2001^[28] as it had been based on data fabricated by Ninov.^[29] This isotope was truly produced in 2010 by the same team; the new data contradicted the previous fabricated data.^[30]

The missing isotopes ²⁷⁸Cn and ²⁷⁹Cn are too heavy to be produced by cold fusion and too light to be produced by hot fusion.Template:Sfn They might be filled from above by decay of heavier elements produced by hot fusion,Template:Sfn and indeed ²⁸⁰Cn and ²⁸¹Cn were produced this way.^[31]^[30] The isotopes ²⁸⁶Cn and ²⁸⁷Cn could be produced by charged-particle evaporation, in the reaction ²⁴⁴Pu(⁴⁸Ca,αxn) with x equalling 1 or 2.^[32]^[33]

Predicted properties

Very few properties of copernicium or its compounds have been measured; this is due to its extremely limited and expensive production^[34] and the fact that copernicium (and its parents) decays very quickly. A few singular chemical properties have been measured, as well as the boiling point, but properties of the copernicium metal remain generally unknown and for the most part, only predictions are available.

Chemical

Copernicium is the tenth and last member of the 6d series and is the heaviest group 12 element in the periodic table, below zinc, cadmium and mercury. It is predicted to differ significantly from the lighter group 12 elements. The valence s-subshells of the group 12 elements and period 7 elements are expected to be relativistically contracted most strongly at copernicium. This and the closed-shell configuration of copernicium result in it probably being a very noble metal. A standard reduction potential of +2.1 V is predicted for the Cn²⁺/Cn couple. Copernicium's predicted first ionization energy of 1155 kJ/mol almost matches that of the noble gas xenon at 1170.4 kJ/mol.^[14] Copernicium's metallic bonds should also be very weak, possibly making it extremely volatile like the noble gases, and potentially making it gaseous at room temperature.^[14]^[35] However, it should be able to form metal–metal bonds with copper, palladium, platinum, silver, and gold; these bonds are predicted to be only about 15–20 kJ/mol weaker than the analogous bonds with mercury.^[14] In opposition to the earlier suggestion,^[36] ab initio calculations at the high level of accuracy^[37] predicted that the chemistry of singly-valent copernicium resembles that of mercury rather than that of the noble gases. The latter result can be explained by the huge spin–orbit interaction which significantly lowers the energy of the vacant 7p_1/2 state of copernicium.

Once copernicium is ionized, its chemistry may present several differences from those of zinc, cadmium, and mercury. Due to the stabilization of 7s electronic orbitals and destabilization of 6d ones caused by relativistic effects, Cn²⁺ is likely to have a [Rn]5f¹⁴6d⁸7s² electronic configuration, using the 6d orbitals before the 7s one, unlike its homologues. The fact that the 6d electrons participate more readily in chemical bonding means that once copernicium is ionized, it may behave more like a transition metal than its lighter homologues, especially in the possible +4 oxidation state. In aqueous solutions, copernicium may form the +2 and perhaps +4 oxidation states.^[14] The diatomic ion Template:Chem, featuring mercury in the +1 oxidation state, is well-known, but the Template:Chem ion is predicted to be unstable or even non-existent.^[14] Copernicium(II) fluoride, CnF₂, should be more unstable than the analogous mercury compound, mercury(II) fluoride (HgF₂), and may even decompose spontaneously into its constituent elements. As the most electronegative reactive element, fluorine may be the only element able to oxidize copernicium even further to the +4 and even +6 oxidation states in CnF₄ and CnF₆; the latter may require matrix-isolation conditions to be detected, as in the disputed detection of HgF₄. CnF₄ should be more stable than CnF₂.^[38] In polar solvents, copernicium is predicted to preferentially form the Template:Chem and Template:Chem anions rather than the analogous neutral fluorides (CnF₄ and CnF₂, respectively), although the analogous bromide or iodide ions may be more stable towards hydrolysis in aqueous solution. The anions Template:Chem and Template:Chem should also be able to exist in aqueous solution.^[14] The formation of thermodynamically stable copernicium(II) and (IV) fluorides would be analogous to the chemistry of xenon.^[39] Analogous to mercury(II) cyanide (Hg(CN)₂), copernicium is expected to form a stable cyanide, Cn(CN)₂.^[40]

Physical and atomic

Copernicium should be a dense metal, with a density of 14.0 g/cm³ in the liquid state at 300 K; this is similar to the known density of mercury, which is 13.534 g/cm³. (Solid copernicium at the same temperature should have a higher density of 14.7 g/cm³.) This results from the effects of copernicium's higher atomic weight being cancelled out by its larger interatomic distances compared to mercury.^[39] Some calculations predicted copernicium to be a gas at room temperature due to its closed-shell electron configuration,^[41] which would make it the first gaseous metal in the periodic table.^[14]^[35] A 2019 calculation agrees with these predictions on the role of relativistic effects, suggesting that copernicium will be a volatile liquid bound by dispersion forces under standard conditions. Its melting point is estimated at Template:Val and its boiling point at Template:Val, the latter in agreement with the experimentally estimated value of Template:Val.^[39] The atomic radius of copernicium is expected to be around 147 pm. Due to the relativistic stabilization of the 7s orbital and destabilization of the 6d orbital, the Cn⁺ and Cn²⁺ ions are predicted to give up 6d electrons instead of 7s electrons, which is the opposite of the behavior of its lighter homologues.^[14]

In addition to the relativistic contraction and binding of the 7s subshell, the 6d_5/2 orbital is expected to be destabilized due to spin–orbit coupling, making it behave similarly to the 7s orbital in terms of size, shape, and energy. Predictions of the expected band structure of copernicium are varied. Calculations in 2007 expected that copernicium may be a semiconductor^[42] with a band gap of around 0.2 eV,^[43] crystallizing in the hexagonal close-packed crystal structure.^[43] However, calculations in 2017 and 2018 suggested that copernicium should be a noble metal at standard conditions with a body-centered cubic crystal structure: it should hence have no band gap, like mercury, although the density of states at the Fermi level is expected to be lower for copernicium than for mercury.^[44]^[45] 2019 calculations then suggested that in fact copernicium has a large band gap of 6.4 ± 0.2 eV, which should be similar to that of the noble gas radon (predicted as 7.1 eV) and would make it an insulator; bulk copernicium is predicted by these calculations to be bound mostly by dispersion forces, like the noble gases.^[39] Like mercury, radon, and flerovium, but not oganesson (eka-radon), copernicium is calculated to have no electron affinity.^[46]

Experimental atomic gas phase chemistry

Interest in copernicium's chemistry was sparked by predictions that it would have the largest relativistic effects in the whole of period 7 and group 12, and indeed among all 118 known elements.^[14] Copernicium is expected to have the ground state electron configuration [Rn] 5f¹⁴ 6d¹⁰ 7s² and thus should belong to group 12 of the periodic table, according to the Aufbau principle. As such, it should behave as the heavier homologue of mercury and form strong binary compounds with noble metals like gold. Experiments probing the reactivity of copernicium have focused on the adsorption of atoms of element 112 onto a gold surface held at varying temperatures, in order to calculate an adsorption enthalpy. Owing to relativistic stabilization of the 7s electrons, copernicium shows radon-like properties. Experiments were performed with the simultaneous formation of mercury and radon radioisotopes, allowing a comparison of adsorption characteristics.^[47]

The first chemical experiments on copernicium were conducted using the ²³⁸U(⁴⁸Ca,3n)²⁸³Cn reaction. Detection was by spontaneous fission of the claimed parent isotope with half-life of 5 minutes. Analysis of the data indicated that copernicium was more volatile than mercury and had noble gas properties. However, the confusion regarding the synthesis of copernicium-283 has cast some doubt on these experimental results.^[47] Given this uncertainty, between April–May 2006 at the JINR, a FLNR–PSI team conducted experiments probing the synthesis of this isotope as a daughter in the nuclear reaction ²⁴²Pu(⁴⁸Ca,3n)²⁸⁷Fl.^[47] (The ²⁴²Pu + ⁴⁸Ca fusion reaction has a slightly larger cross-section than the ²³⁸U + ⁴⁸Ca reaction, so that the best way to produce copernicium for chemical experimentation is as an overshoot product as the daughter of flerovium.)^[48] In this experiment, two atoms of copernicium-283 were unambiguously identified and the adsorption properties were interpreted to show that copernicium is a more volatile homologue of mercury, due to formation of a weak metal-metal bond with gold.^[47] This agrees with general indications from some relativistic calculations that copernicium is "more or less" homologous to mercury.^[49] However, it was pointed out in 2019 that this result may simply be due to strong dispersion interactions.^[39]

In April 2007, this experiment was repeated and a further three atoms of copernicium-283 were positively identified. The adsorption property was confirmed and indicated that copernicium has adsorption properties in agreement with being the heaviest member of group 12.^[47] These experiments also allowed the first experimental estimation of copernicium's boiling point: 84Template:Su °C, so that it may be a gas at standard conditions.^[42]

Because the lighter group 12 elements often occur as chalcogenide ores, experiments were conducted in 2015 to deposit copernicium atoms on a selenium surface to form copernicium selenide, CnSe. Reaction of copernicium atoms with trigonal selenium to form a selenide was observed, with -ΔH_ads^Cn(t-Se) > 48 kJ/mol, with the kinetic hindrance towards selenide formation being lower for copernicium than for mercury. This was unexpected as the stability of the group 12 selenides tends to decrease down the group from ZnSe to HgSe.^[50]

Notes

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References

Template:Reflist

Bibliography

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External links

Template:Sister project Template:Sister project

Copernicium at The Periodic Table of Videos (University of Nottingham)

Template:Nicolaus Copernicus Template:Periodic table (navbox) Template:Authority control

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 |publisher=[[World Scientific]]
 |doi=10.1142/9789812701749_0027
-}}</ref><ref>{{Cite journal | doi=10.7566/JPSJ.82.024202|title = New Result on the Production of277Cn by the208Pb +70Zn Reaction| journal=Journal of the Physical Society of Japan| volume=82| issue=2| pages=024202|year = 2013|last1 = Sumita|first1 = Takayuki| last2=Morimoto| first2=Kouji| last3=Kaji| first3=Daiya| last4=Haba| first4=Hiromitsu| last5=Ozeki| first5=Kazutaka| last6=Sakai| first6=Ryutaro| last7=Yoneda| first7=Akira| last8=Yoshida| first8=Atsushi| last9=Hasebe| first9=Hiroo| last10=Katori| first10=Kenji| last11=Sato| first11=Nozomi| last12=Wakabayashi| first12=Yasuo| last13=Mitsuoka| first13=Shin-Ichi| last14=Goto| first14=Shin-Ichi| last15=Murakami| first15=Masashi| last16=Kariya| first16=Yoshiki| last17=Tokanai| first17=Fuyuki| last18=Mayama| first18=Keita| last19=Takeyama| first19=Mirei| last20=Moriya| first20=Toru| last21=Ideguchi| first21=Eiji| last22=Yamaguchi| first22=Takayuki| last23=Kikunaga| first23=Hidetoshi| last24=Chiba| first24=Junsei| last25=Morita| first25=Kosuke|bibcode = 2013JPSJ...82b4202S}}</ref> This reaction had also previously been tried in 1971 at the [[Joint Institute for Nuclear Research]] in [[Dubna]], [[Russia]] to aim for <sup>276</sup>Cn (produced in the 2n channel), but without success.<ref>{{cite web |url=https://newuc.jinr.ru/img_sections/file/Practice2016/EU/2016-07%20AGP_SHE.pdf |title=Synthesis of superheavy elements |last=Popeko |first=Andrey G. |date=2016 |website=jinr.ru |publisher=[[Joint Institute for Nuclear Research]] |access-date=4 February 2018 |archive-url=https://web.archive.org/web/20180204124109/https://newuc.jinr.ru/img_sections/file/Practice2016/EU/2016-07%20AGP_SHE.pdf |archive-date=4 February 2018 |url-status=dead }}</ref>
+}}</ref><ref>{{Cite journal | doi=10.7566/JPSJ.82.024202|title = New Result on the Production of277Cn by the208Pb +70Zn Reaction| journal=Journal of the Physical Society of Japan| volume=82| issue=2| article-number=024202|year = 2013|last1 = Sumita|first1 = Takayuki| last2=Morimoto| first2=Kouji| last3=Kaji| first3=Daiya| last4=Haba| first4=Hiromitsu| last5=Ozeki| first5=Kazutaka| last6=Sakai| first6=Ryutaro| last7=Yoneda| first7=Akira| last8=Yoshida| first8=Atsushi| last9=Hasebe| first9=Hiroo| last10=Katori| first10=Kenji| last11=Sato| first11=Nozomi| last12=Wakabayashi| first12=Yasuo| last13=Mitsuoka| first13=Shin-Ichi| last14=Goto| first14=Shin-Ichi| last15=Murakami| first15=Masashi| last16=Kariya| first16=Yoshiki| last17=Tokanai| first17=Fuyuki| last18=Mayama| first18=Keita| last19=Takeyama| first19=Mirei| last20=Moriya| first20=Toru| last21=Ideguchi| first21=Eiji| last22=Yamaguchi| first22=Takayuki| last23=Kikunaga| first23=Hidetoshi| last24=Chiba| first24=Junsei| last25=Morita| first25=Kosuke|bibcode = 2013JPSJ...82b4202S}}</ref> This reaction had also previously been tried in 1971 at the [[Joint Institute for Nuclear Research]] in [[Dubna]], [[Russia]], to aim for <sup>276</sup>Cn (produced in the 2n channel), but without success.<ref>{{cite web |url=https://newuc.jinr.ru/img_sections/file/Practice2016/EU/2016-07%20AGP_SHE.pdf |title=Synthesis of superheavy elements |last=Popeko |first=Andrey G. |date=2016 |website=jinr.ru |publisher=[[Joint Institute for Nuclear Research]] |access-date=4 February 2018 |archive-url=https://web.archive.org/web/20180204124109/https://newuc.jinr.ru/img_sections/file/Practice2016/EU/2016-07%20AGP_SHE.pdf |archive-date=4 February 2018 }}</ref>
 The [[IUPAC/IUPAP Joint Working Party]] (JWP) assessed the claim of copernicium's discovery by the GSI team in 2001<ref>{{cite journal
@@ Line 93: / Line 92: @@
 |archive-url=https://web.archive.org/web/20180309212208/https://www.iupac.org/publications/pac/2001/pdf/7306x0959.pdf
 |archive-date=9 March 2018
-|url-status=dead
 }}</ref> and 2003.<ref>{{cite journal
 |last1=Karol
@@ Line 115: / Line 113: @@
 |archive-url=https://web.archive.org/web/20160822073903/https://www.iupac.org/publications/pac/2003/pdf/7510x1601.pdf
 |archive-date=22 August 2016
-|url-status=dead
 }}</ref> In both cases, they found that there was insufficient evidence to support their claim. This was primarily related to the contradicting decay data for the known [[nuclide]] rutherfordium-261. However, between 2001 and 2005, the GSI team studied the reaction <sup>248</sup>Cm(<sup>26</sup>Mg,5n)<sup>269</sup>Hs, and were able to confirm the decay data for [[hassium-269]] and [[rutherfordium-261]]. It was found that the existing data on rutherfordium-261 was for an [[Nuclear isomer|isomer]],<ref>
 {{cite web
@@ Line 127: / Line 124: @@
 |work=Annual Report
 |publisher=[[Paul Scherrer Institute]]
-|url-status=dead
 |archive-url=https://web.archive.org/web/20110707001918/https://lch.web.psi.ch/files/anrep01/B-02heavies.pdf
 |archive-date=2011-07-07
@@ Line 140: / Line 136: @@
 |archive-url  = https://web.archive.org/web/20090823022637/https://www.gsi.de/portrait/Pressemeldungen/10062009_e.html
 |archive-date = 23 August 2009
-|url-status   = dead
 }}</ref> This decision was based on the confirmation of the decay properties of daughter nuclei as well as the confirmatory experiments at RIKEN.<ref name="fusion">{{cite journal
 |last1=Barber
@@ Line 157: / Line 152: @@
 |archive-date=2012-11-28
 |archive-url=https://web.archive.org/web/20121128020041/http://pac.iupac.org/publications/pac/pdf/2009/pdf/8107x1331.pdf
-|url-status=dead
 }}</ref>
-Work had also been done at the [[Joint Institute for Nuclear Research]] in [[Dubna]], Russia from 1998 to synthesise the heavier isotope <sup>283</sup>Cn in the hot fusion reaction <sup>238</sup>U(<sup>48</sup>Ca,3n)<sup>283</sup>Cn; most observed atoms of <sup>283</sup>Cn decayed by spontaneous fission, although an alpha decay branch to <sup>279</sup>Ds was detected. While initial experiments aimed to assign the produced nuclide with its observed long half-life of 3&nbsp;minutes based on its chemical behaviour, this was found to be not mercury-like as would have been expected (copernicium being under mercury in the periodic table),<ref name="fusion" /> and indeed now it appears that the long-lived activity might not have been from <sup>283</sup>Cn at all, but its [[electron capture]] daughter <sup>283</sup>Rg instead, with a shorter 4-second half-life associated with <sup>283</sup>Cn. (Another possibility is assignment to a [[meta state|metastable isomeric state]], <sup>283m</sup>Cn.)<ref name="EXON">{{cite conference |title=Remarks on the Fission Barriers of SHN and Search for Element 120 |first1=S. |last1=Hofmann |first2=S. |last2=Heinz |first3=R. |last3=Mann |first4=J. |last4=Maurer |first5=G. |last5=Münzenberg |first6=S. |last6=Antalic |first7=W. |last7=Barth |first8=H. G. |last8=Burkhard |first9=L. |last9=Dahl |first10=K. |last10=Eberhardt |first11=R. |last11=Grzywacz |first12=J. H. |last12=Hamilton |first13=R. A. |last13=Henderson |first14=J. M. |last14=Kenneally |first15=B. |last15=Kindler |first16=I. |last16=Kojouharov |first17=R. |last17=Lang |first18=B. |last18=Lommel |first19=K. |last19=Miernik |first20=D. |last20=Miller |first21=K. J. |last21=Moody |first22=K. |last22=Morita |first23=K. |last23=Nishio |first24=A. G. |last24=Popeko |first25=J. B. |last25=Roberto |first26=J. |last26=Runke |first27=K. P. |last27=Rykaczewski |first28=S. |last28=Saro |first29=C. |last29=Schneidenberger |first30=H. J. |last30=Schött |first31=D. A. |last31=Shaughnessy |first32=M. A. |last32=Stoyer |first33=P. |last33=Thörle-Pospiech |first34=K. |last34=Tinschert |first35=N. |last35=Trautmann |first36=J. |last36=Uusitalo |first37=A. V. |last37=Yeremin |year=2016 |conference=Exotic Nuclei |editor1-first=Yu. E. |editor1-last=Peninozhkevich |editor2-first=Yu. G. |editor2-last=Sobolev |book-title=Exotic Nuclei: EXON-2016 Proceedings of the International Symposium on Exotic Nuclei |pages=155–164 |isbn=9789813226555}}</ref> While later cross-bombardments in the <sup>242</sup>Pu+<sup>48</sup>Ca and <sup>245</sup>Cm+<sup>48</sup>Ca reactions succeeded in confirming the properties of <sup>283</sup>Cn and its parents <sup>287</sup>Fl and <sup>291</sup>Lv, and played a major role in the acceptance of the discoveries of [[flerovium]] and [[livermorium]] (elements 114 and 116) by the JWP in 2011, this work originated subsequent to the GSI's work on <sup>277</sup>Cn and priority was assigned to the GSI.<ref name="fusion" />
+Work had also been done at the [[Joint Institute for Nuclear Research]] in [[Dubna]], Russia from 1998 to synthesize the heavier isotope <sup>283</sup>Cn in the hot fusion reaction <sup>238</sup>U(<sup>48</sup>Ca,3n)<sup>283</sup>Cn; most observed atoms of <sup>283</sup>Cn decayed by spontaneous fission, although an alpha decay branch to <sup>279</sup>Ds was detected. While initial experiments aimed to assign the produced nuclide with its observed long half-life of 3&nbsp;minutes based on its chemical behaviour, this was found to be not mercury-like as would have been expected (copernicium being under mercury in the periodic table),<ref name="fusion" /> and indeed now it appears that the long-lived activity might not have been from <sup>283</sup>Cn at all, but its [[electron capture]] daughter <sup>283</sup>Rg instead, with a shorter 4-second half-life associated with <sup>283</sup>Cn. (Another possibility is assignment to a [[meta state|metastable isomeric state]], <sup>283m</sup>Cn.)<ref name="EXON">{{cite conference |title=Remarks on the Fission Barriers of SHN and Search for Element 120 |first1=S. |last1=Hofmann |first2=S. |last2=Heinz |first3=R. |last3=Mann |first4=J. |last4=Maurer |first5=G. |last5=Münzenberg |first6=S. |last6=Antalic |first7=W. |last7=Barth |first8=H. G. |last8=Burkhard |first9=L. |last9=Dahl |first10=K. |last10=Eberhardt |first11=R. |last11=Grzywacz |first12=J. H. |last12=Hamilton |first13=R. A. |last13=Henderson |first14=J. M. |last14=Kenneally |first15=B. |last15=Kindler |first16=I. |last16=Kojouharov |first17=R. |last17=Lang |first18=B. |last18=Lommel |first19=K. |last19=Miernik |first20=D. |last20=Miller |first21=K. J. |last21=Moody |first22=K. |last22=Morita |first23=K. |last23=Nishio |first24=A. G. |last24=Popeko |first25=J. B. |last25=Roberto |first26=J. |last26=Runke |first27=K. P. |last27=Rykaczewski |first28=S. |last28=Saro |first29=C. |last29=Schneidenberger |first30=H. J. |last30=Schött |first31=D. A. |last31=Shaughnessy |first32=M. A. |last32=Stoyer |first33=P. |last33=Thörle-Pospiech |first34=K. |last34=Tinschert |first35=N. |last35=Trautmann |first36=J. |last36=Uusitalo |first37=A. V. |last37=Yeremin |year=2016 |conference=Exotic Nuclei |editor1-first=Yu. E. |editor1-last=Peninozhkevich |editor2-first=Yu. G. |editor2-last=Sobolev |book-title=Exotic Nuclei: EXON-2016 Proceedings of the International Symposium on Exotic Nuclei |pages=155–164 |isbn=978-981-322-655-5}}</ref> While later cross-bombardments in the <sup>242</sup>Pu+<sup>48</sup>Ca and <sup>245</sup>Cm+<sup>48</sup>Ca reactions succeeded in confirming the properties of <sup>283</sup>Cn and its parents <sup>287</sup>Fl and <sup>291</sup>Lv, and played a major role in the acceptance of the discoveries of [[flerovium]] and [[livermorium]] (elements 114 and 116) by the JWP in 2011, this work originated subsequent to the GSI's work on <sup>277</sup>Cn and priority was assigned to the GSI.<ref name="fusion" />
 ===Naming===
-[[File:Nikolaus Kopernikus.jpg|thumb|upright|right|alt=a painted portrait of Copernicus|[[Nicolaus Copernicus]], who formulated a heliocentric model with the planets orbiting around the Sun, replacing [[Ptolemy]]'s earlier geocentric model. |185x185px]]
+[[File:Nikolaus Kopernikus.jpg|thumb|upright|right|alt=a painted portrait of Copernicus|[[Nicolaus Copernicus]], who formulated a heliocentric model with the planets orbiting around the Sun, replacing [[Ptolemy]]'s earlier geocentric model |185x185px]]
 Using [[Mendeleev's predicted elements|Mendeleev's nomenclature for unnamed and undiscovered elements]], copernicium should be known as ''eka-[[mercury (element)|mercury]]''. In 1979, IUPAC published recommendations according to which the element was to be called ''ununbium'' (with the corresponding symbol of ''Uub''),<ref name="iupac">{{cite journal|author=Chatt, 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 on. Although widely used in the chemical community on all levels, from chemistry classrooms to advanced textbooks, the recommendations were mostly ignored among scientists in the field, who either called it "element 112", with the symbol of ''E112'', ''(112)'', or even simply ''112''.<ref name="Haire" />
@@ Line 181: / Line 175: @@
 |url=https://www.gsi.de/portrait/Pressemeldungen/14072009_e.html
 |publisher=[[Gesellschaft für Schwerionenforschung]]
-|url-status=dead
 |archive-url=https://web.archive.org/web/20090718113516/https://www.gsi.de/portrait/Pressemeldungen/14072009_e.html
 |archive-date=18 July 2009
@@ Line 203: / Line 196: @@
 |archive-url  = https://web.archive.org/web/20121127231211/https://www.iupac.org/news/news-detail/article/start-of-the-name-approval-process-for-the-element-of-atomic-number-112.html
 |archive-date = 27 November 2012
-|url-status   = dead
 }}</ref>
 it was pointed out that the symbol ''Cp'' was previously associated with the name ''cassiopeium'' (cassiopium), now known as [[lutetium]] (Lu).<ref>
@@ Line 234: / Line 226: @@
 |archive-url  = https://web.archive.org/web/20160304090404/https://stage.iupac.org/web/nt/2010-02-20_112_Copernicium
 |archive-date = 4 March 2016
-|url-status   = dead
 }}</ref>
 {{clear}}
@@ Line 253: / Line 244: @@
 }}
 {{isotopes summary/isotope
-|mn=281 |sym=Cn |hl={{sort|180|0.18 s}} |ref=<ref name=PuCa2017>{{cite journal |last1=Utyonkov |first1=V. K. |last2=Brewer |first2=N. T. |first3=Yu. Ts. |last3=Oganessian |first4=K. P. |last4=Rykaczewski |first5=F. Sh. |last5=Abdullin |first6=S. N. |last6=Dimitriev |first7=R. K. |last7=Grzywacz |first8=M. G. |last8=Itkis |first9=K. |last9=Miernik |first10=A. N. |last10=Polyakov |first11=J. B. |last11=Roberto |first12=R. N. |last12=Sagaidak |first13=I. V. |last13=Shirokovsky |first14=M. V. |last14=Shumeiko |first15=Yu. S. |last15=Tsyganov |first16=A. A. |last16=Voinov |first17=V. G. |last17=Subbotin |first18=A. M. |last18=Sukhov |first19=A. V. |last19=Karpov |first20=A. G. |last20=Popeko |first21=A. V. |last21=Sabel'nikov |first22=A. I. |last22=Svirikhin |first23=G. K. |last23=Vostokin |first24=J. H. |last24=Hamilton |first25=N. D. |last25=Kovrinzhykh |first26=L. |last26=Schlattauer |first27=M. A. |last27=Stoyer |first28=Z. |last28=Gan |first29=W. X. |last29=Huang |first30=L. |last30=Ma |date=30 January 2018 |display-authors=3 |title=Neutron-deficient superheavy nuclei obtained in the <sup>240</sup>Pu+<sup>48</sup>Ca reaction |journal=Physical Review C |volume=97 |issue=14320 |page=014320 |doi=10.1103/PhysRevC.97.014320|bibcode=2018PhRvC..97a4320U|doi-access=free }}</ref>
+|mn=281 |sym=Cn |hl={{sort|180|0.18 s}} |ref=<ref name=PuCa2017>{{cite journal |last1=Utyonkov |first1=V. K. |last2=Brewer |first2=N. T. |first3=Yu. Ts. |last3=Oganessian |first4=K. P. |last4=Rykaczewski |first5=F. Sh. |last5=Abdullin |first6=S. N. |last6=Dimitriev |first7=R. K. |last7=Grzywacz |first8=M. G. |last8=Itkis |first9=K. |last9=Miernik |first10=A. N. |last10=Polyakov |first11=J. B. |last11=Roberto |first12=R. N. |last12=Sagaidak |first13=I. V. |last13=Shirokovsky |first14=M. V. |last14=Shumeiko |first15=Yu. S. |last15=Tsyganov |first16=A. A. |last16=Voinov |first17=V. G. |last17=Subbotin |first18=A. M. |last18=Sukhov |first19=A. V. |last19=Karpov |first20=A. G. |last20=Popeko |first21=A. V. |last21=Sabel'nikov |first22=A. I. |last22=Svirikhin |first23=G. K. |last23=Vostokin |first24=J. H. |last24=Hamilton |first25=N. D. |last25=Kovrinzhykh |first26=L. |last26=Schlattauer |first27=M. A. |last27=Stoyer |first28=Z. |last28=Gan |first29=W. X. |last29=Huang |first30=L. |last30=Ma |date=30 January 2018 |display-authors=3 |title=Neutron-deficient superheavy nuclei obtained in the <sup>240</sup>Pu+<sup>48</sup>Ca reaction |journal=Physical Review C |volume=97 |issue=14320 |article-number=014320 |doi=10.1103/PhysRevC.97.014320|bibcode=2018PhRvC..97a4320U|doi-access=free }}</ref>
 |dm=α |year=2010 |re=<sup>285</sup>Fl(—,α)
 }}
@@ Line 265: / Line 256: @@
 }}
 {{isotopes summary/isotope
-|mn=284 |sym=Cn |hl={{sort|121|121 ms}} |ref=<ref name=280Ds2021>{{Cite journal |doi = 10.1103/PhysRevLett.126.032503|title = Spectroscopy along Flerovium Decay Chains: Discovery of <sup>280</sup>Ds and an Excited State in <sup>282</sup>Cn|journal = Physical Review Letters|volume = 126|pages = 032503|year = 2021|last1 = Såmark-Roth|first1 = A.|last2 = Cox|first2 = D. M.|last3 = Rudolph|first3 = D.|last4 = Sarmento|first4 = L. G.|last5 = Carlsson|first5 = B. G.|last6 = Egido|first6 = J. L.|last7 = Golubev|first7 = P|last8 = Heery|first8 = J.|last9 = Yakushev|first9 = A.|last10 = Åberg|first10 = S.|last11 = Albers|first11 = H. M.|last12 = Albertsson|first12 = M.|last13 = Block|first13 = M.|last14 = Brand|first14 = H.|last15 = Calverley|first15 = T.|last16 = Cantemir|first16 = R.|last17 = Clark|first17 = R. M.|last18 = Düllmann|first18 = Ch. E.|last19 = Eberth|first19 = J.|last20 = Fahlander|first20 = C.|last21 = Forsberg|first21 = U.|last22 = Gates|first22 = J. M.|last23 = Giacoppo|first23 = F.|last24 = Götz|first24 = M.|last25 = Hertzberg|first25 = R.-D.|last26 = Hrabar|first26 = Y.|last27 = Jäger|first27 = E.|last28 = Judson|first28 = D.|last29 = Khuyagbaatar|first29 = J.|last30 = Kindler|first30 = B.| issue=3 | pmid=33543956 | bibcode=2021PhRvL.126c2503S | s2cid=231818619 |display-authors = 3|doi-access = free|hdl = 10486/705608|hdl-access = free}}</ref>
+|mn=284 |sym=Cn |hl={{sort|121|121 ms}} |ref=<ref name=280Ds2021>{{Cite journal |doi = 10.1103/PhysRevLett.126.032503|title = Spectroscopy along Flerovium Decay Chains: Discovery of <sup>280</sup>Ds and an Excited State in <sup>282</sup>Cn|journal = Physical Review Letters|volume = 126|article-number = 032503|year = 2021|last1 = Såmark-Roth|first1 = A.|last2 = Cox|first2 = D. M.|last3 = Rudolph|first3 = D.|last4 = Sarmento|first4 = L. G.|last5 = Carlsson|first5 = B. G.|last6 = Egido|first6 = J. L.|last7 = Golubev|first7 = P|last8 = Heery|first8 = J.|last9 = Yakushev|first9 = A.|last10 = Åberg|first10 = S.|last11 = Albers|first11 = H. M.|last12 = Albertsson|first12 = M.|last13 = Block|first13 = M.|last14 = Brand|first14 = H.|last15 = Calverley|first15 = T.|last16 = Cantemir|first16 = R.|last17 = Clark|first17 = R. M.|last18 = Düllmann|first18 = Ch. E.|last19 = Eberth|first19 = J.|last20 = Fahlander|first20 = C.|last21 = Forsberg|first21 = U.|last22 = Gates|first22 = J. M.|last23 = Giacoppo|first23 = F.|last24 = Götz|first24 = M.|last25 = Hertzberg|first25 = R.-D.|last26 = Hrabar|first26 = Y.|last27 = Jäger|first27 = E.|last28 = Judson|first28 = D.|last29 = Khuyagbaatar|first29 = J.|last30 = Kindler|first30 = B.| issue=3 | pmid=33543956 | bibcode=2021PhRvL.126c2503S | s2cid=231818619 |display-authors = 3|doi-access = free|hdl = 10486/705608|hdl-access = free}}</ref>
 |dm=α, SF |year=2004 |re=<sup>288</sup>Fl(—,α)
 }}
@@ Line 280: / Line 271: @@
 |dm=SF |year=2016 |re=<sup>294</sup>Lv(—,2α)
 }}}}
-Copernicium 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. Eight different isotopes have been reported with mass numbers 277 and 280–286, and one unconfirmed [[nuclear isomer|metastable isomer]] in <sup>285</sup>Cn has been reported.<ref name="gsi12">{{cite journal |doi=10.1140/epja/i2012-12062-1 |volume=48 |issue=5 |pages=62 |title=The reaction <sup>48</sup>Ca + <sup>248</sup>Cm → <sup>296</sup>116<sup>*</sup> studied at the GSI-SHIP |journal=The European Physical Journal A| year=2012 |last1=Hofmann |first1=S. |last2=Heinz |first2=S. |last3=Mann |first3=R. |last4=Maurer |first4=J. |last5=Khuyagbaatar |first5=J. |last6=Ackermann |first6=D. |last7=Antalic |first7=S. |last8=Barth |first8=W. |last9=Block |first9=M. |last10=Burkhard |first10=H. G. |last11=Comas |first11=V. F. |last12=Dahl |first12=L. |last13=Eberhardt |first13=K. |last14=Gostic |first14=J. |last15=Henderson |first15=R. A. |last16=Heredia |first16=J. A. |last17=Heßberger |first17=F. P. |last18=Kenneally |first18=J. M. |last19=Kindler |first19=B. |last20=Kojouharov |first20=I. |last21=Kratz |first21=J. V. |last22=Lang |first22=R. |last23=Leino |first23=M. |last24=Lommel |first24=B. |last25=Moody |first25=K. J. |last26=Münzenberg |first26=G. |last27=Nelson |first27=S. L. |last28=Nishio |first28=K. |last29=Popeko |first29=A. G. |last30=Runke |first30=J. |last31=Saro |first31=S. |last32=Shaughnessy |first32=D. A. |last33=Leino |first33=M. |last34=Lommel |first34=B. |last35=Moody |first35=K. J. |last36=Münzenberg |first36=G. |last37=Stoyer |first37=M. A. |last38=Thörle-Pospiech |first38=P. |last39=Tinschert |first39=K. |last40=Trautmann |first40=N. |last41=Uusitalo |first41=J. |last42=Wilk |first42=P. A. |last43=Yeremin |first43=A. V. | display-authors=3 | bibcode=2012EPJA...48...62H| s2cid=121930293}}</ref> Most of these decay predominantly through alpha decay, but some undergo [[spontaneous fission]], and copernicium-283 may have an [[electron capture]] branch.<ref name="nuclidetable">
+Copernicium 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. Eight different isotopes have been reported with mass numbers 277 and 280–286, and one unconfirmed [[nuclear isomer|metastable isomer]] in <sup>285</sup>Cn has been reported.<ref name="gsi12">{{cite journal |doi=10.1140/epja/i2012-12062-1 |volume=48 |issue=5 |page=62 |title=The reaction <sup>48</sup>Ca + <sup>248</sup>Cm → <sup>296</sup>116<sup>*</sup> studied at the GSI-SHIP |journal=The European Physical Journal A| year=2012 |last1=Hofmann |first1=S. |last2=Heinz |first2=S. |last3=Mann |first3=R. |last4=Maurer |first4=J. |last5=Khuyagbaatar |first5=J. |last6=Ackermann |first6=D. |last7=Antalic |first7=S. |last8=Barth |first8=W. |last9=Block |first9=M. |last10=Burkhard |first10=H. G. |last11=Comas |first11=V. F. |last12=Dahl |first12=L. |last13=Eberhardt |first13=K. |last14=Gostic |first14=J. |last15=Henderson |first15=R. A. |last16=Heredia |first16=J. A. |last17=Heßberger |first17=F. P. |last18=Kenneally |first18=J. M. |last19=Kindler |first19=B. |last20=Kojouharov |first20=I. |last21=Kratz |first21=J. V. |last22=Lang |first22=R. |last23=Leino |first23=M. |last24=Lommel |first24=B. |last25=Moody |first25=K. J. |last26=Münzenberg |first26=G. |last27=Nelson |first27=S. L. |last28=Nishio |first28=K. |last29=Popeko |first29=A. G. |last30=Runke |first30=J. |last31=Saro |first31=S. |last32=Shaughnessy |first32=D. A. |last33=Leino |first33=M. |last34=Lommel |first34=B. |last35=Moody |first35=K. J. |last36=Münzenberg |first36=G. |last37=Stoyer |first37=M. A. |last38=Thörle-Pospiech |first38=P. |last39=Tinschert |first39=K. |last40=Trautmann |first40=N. |last41=Uusitalo |first41=J. |last42=Wilk |first42=P. A. |last43=Yeremin |first43=A. V. | display-authors=3 | bibcode=2012EPJA...48...62H| s2cid=121930293}}</ref> Most of these decay predominantly through alpha decay, but some undergo [[spontaneous fission]], and copernicium-283 may have an [[electron capture]] branch.<ref name="nuclidetable">
 {{cite book
 |last1=Holden
@@ Line 311: / Line 302: @@
 |archive-date=2016-03-04
 |archive-url=https://web.archive.org/web/20160304084257/http://pac.iupac.org/publications/pac/pdf/2011/pdf/8307x1485.pdf
-|url-status=dead
 }}</ref>
@@ Line 345: / Line 335: @@
 |archive-url  = https://web.archive.org/web/20080129191344/https://enews.lbl.gov/Science-Articles/Archive/118-retraction.html
 |archive-date = 29 January 2008
-|url-status   = dead
 }}</ref> as it had been based on data fabricated by Ninov.<ref name="NYT20021015">[https://www.nytimes.com/2002/10/15/science/at-lawrence-berkeley-physicists-say-a-colleague-took-them-for-a-ride.html?scp=2&sq=victor%20ninov&st=cse&pagewanted=1 "At Lawrence Berkeley, Physicists Say a Colleague Took Them for a Ride"] {{Webarchive|url=https://web.archive.org/web/20230815020439/https://www.nytimes.com/2002/10/15/science/at-lawrence-berkeley-physicists-say-a-colleague-took-them-for-a-ride.html?scp=2&sq=victor%20ninov&st=cse&pagewanted=1 |date=2023-08-15 }} George Johnson, ''The New York Times'', 15 October 2002</ref> This isotope was truly produced in 2010 by the same team; the new data contradicted the previous fabricated data.<ref name="281Cn">{{Cite news
 |author=Public Affairs Department
@@ Line 364: / Line 353: @@
 ===Chemical===
-Copernicium is the tenth and last member of the 6d series and is the heaviest [[group 12 element]] in the periodic table, below [[zinc]], [[cadmium]] and [[mercury (element)|mercury]]. It is predicted to differ significantly from the lighter group&nbsp;12 elements. The valence s-[[Electron shell#Subshells|subshells]] of the group 12 elements and period 7 elements are expected to be relativistically contracted most strongly at copernicium. This and the closed-shell configuration of copernicium result in it probably being a very [[noble metal]]. A [[standard reduction potential]] of +2.1&nbsp;V is predicted for the Cn<sup>2+</sup>/Cn couple. Copernicium's predicted first ionization energy of 1155&nbsp;kJ/mol almost matches that of the noble gas [[xenon]] at 1170.4&nbsp;kJ/mol.<ref name="Haire" /> Copernicium's [[metallic bond]]s should also be very weak, possibly making it extremely volatile like the noble gases, and potentially making it gaseous at room temperature.<ref name="Haire" /><ref name="NS1975">"Chemistry on the islands of stability", ''New Scientist'', 11 September 1975, p. 574, {{ISSN|1032-1233}}</ref> However, it should be able to form metal–metal bonds with [[copper]], [[palladium]], [[platinum]], [[silver]], and [[gold]]; these bonds are predicted to be only about 15–20&nbsp;[[kilojoule per mole|kJ/mol]] weaker than the analogous bonds with mercury.<ref name="Haire" /> In opposition to the earlier suggestion,<ref name="Eliav1995">{{cite journal |last1=Pitzer |first1=K. S. |title=Are elements 112, 114, and 118 relatively inert gases? |journal=The Journal of Chemical Physics |volume=63 |issue=2 |pages=1032–1033 |year=1975 |doi=10.1063/1.431398 |url=https://escholarship.org/uc/item/2qw742ss |access-date=2019-07-08 |archive-date=2024-10-08 |archive-url=https://web.archive.org/web/20241008110131/https://escholarship.org/uc/item/2qw742ss |url-status=live }}</ref> ab initio calculations at the high level of accuracy<ref name="Mosyagin2006">{{cite journal |last1=Mosyagin |first1=N. S. |last2=Isaev |first2=T. A. |last3=Titov |first3=A. V. |title=Is E112 a relatively inert element? Benchmark relativistic correlation study of spectroscopic constants in E112H and its cation |journal=The Journal of Chemical Physics |volume=124 |issue=22 |pages=224302 |year=2006 |doi=10.1063/1.2206189 |pmid=16784269 |bibcode=2006JChPh.124v4302M |arxiv=physics/0508024|s2cid=119339584 }}</ref> predicted that the chemistry of singly-valent copernicium resembles that of mercury rather than that of the noble gases. The latter result can be explained by the huge [[spin–orbit interaction]] which significantly lowers the energy of the vacant 7p<sub>1/2</sub> state of copernicium.
+Copernicium is the tenth and last member of the 6d series and is the heaviest [[group 12 element]] in the periodic table, below [[zinc]], [[cadmium]] and [[mercury (element)|mercury]]. It is predicted to differ significantly from the lighter group&nbsp;12 elements. The valence s-[[Electron shell#Subshells|subshells]] of the group 12 elements and period 7 elements are expected to be relativistically contracted most strongly at copernicium. This and the closed-shell configuration of copernicium result in it probably being a very [[noble metal]]. A [[standard reduction potential]] of +2.1&nbsp;V is predicted for the Cn<sup>2+</sup>/Cn couple. Copernicium's predicted first ionization energy of 1155&nbsp;kJ/mol almost matches that of the noble gas [[xenon]] at 1170.4&nbsp;kJ/mol.<ref name="Haire" /> Copernicium's [[metallic bond]]s should also be very weak, possibly making it extremely volatile like the noble gases, and potentially making it gaseous at room temperature.<ref name="Haire" /><ref name="NS1975">"Chemistry on the islands of stability", ''New Scientist'', 11 September 1975, p. 574, {{ISSN|1032-1233}}</ref> However, it should be able to form metal–metal bonds with [[copper]], [[palladium]], [[platinum]], [[silver]], and [[gold]]; these bonds are predicted to be only about 15–20&nbsp;[[kilojoule per mole|kJ/mol]] weaker than the analogous bonds with mercury.<ref name="Haire" /> In opposition to the earlier suggestion,<ref name="Eliav1995">{{cite journal |last1=Pitzer |first1=K. S. |title=Are elements 112, 114, and 118 relatively inert gases? |journal=The Journal of Chemical Physics |volume=63 |issue=2 |pages=1032–1033 |year=1975 |doi=10.1063/1.431398 |url=https://escholarship.org/uc/item/2qw742ss |access-date=2019-07-08 |archive-date=2024-10-08 |archive-url=https://web.archive.org/web/20241008110131/https://escholarship.org/uc/item/2qw742ss |url-status=live }}</ref> ab initio calculations at the high level of accuracy<ref name="Mosyagin2006">{{cite journal |last1=Mosyagin |first1=N. S. |last2=Isaev |first2=T. A. |last3=Titov |first3=A. V. |title=Is E112 a relatively inert element? Benchmark relativistic correlation study of spectroscopic constants in E112H and its cation |journal=The Journal of Chemical Physics |volume=124 |issue=22 |page=224302 |year=2006 |doi=10.1063/1.2206189 |pmid=16784269 |bibcode=2006JChPh.124v4302M |arxiv=physics/0508024|s2cid=119339584 }}</ref> predicted that the chemistry of singly-valent copernicium resembles that of mercury rather than that of the noble gases. The latter result can be explained by the huge [[spin–orbit interaction]] which significantly lowers the energy of the vacant 7p<sub>1/2</sub> state of copernicium.
-Once copernicium is ionized, its chemistry may present several differences from those of zinc, cadmium, and mercury. Due to the stabilization of 7s electronic orbitals and destabilization of 6d ones caused by [[Relativistic quantum chemistry|relativistic effects]], Cn<sup>2+</sup> is likely to have a [Rn]5f<sup>14</sup>6d<sup>8</sup>7s<sup>2</sup> [[electronic configuration]], using the 6d orbitals before the 7s one, unlike its homologues. The fact that the 6d electrons participate more readily in chemical bonding means that once copernicium is ionized, it may behave more like a [[transition metal]] than its lighter [[Homologous series|homologues]], especially in the possible +4 oxidation state. In [[aqueous solution]]s, copernicium may form the +2 and perhaps +4 oxidation states.<ref name="Haire" /> The diatomic ion {{chem|Hg|2|2+}}, featuring mercury in the +1 oxidation state, is well-known, but the {{chem|Cn|2|2+}} ion is predicted to be unstable or even non-existent.<ref name="Haire" /> Copernicium(II) fluoride, CnF<sub>2</sub>, should be more unstable than the analogous mercury compound, [[mercury(II) fluoride]] (HgF<sub>2</sub>), and may even decompose spontaneously into its constituent elements. As the most electronegative reactive element, fluorine may be the only element able to oxidise copernicium even further to the +4 and even +6 oxidation states in CnF<sub>4</sub> and CnF<sub>6</sub>; the latter may require matrix-isolation conditions to be detected, as in the disputed detection of [[mercury(IV) fluoride|HgF<sub>4</sub>]]. CnF<sub>4</sub> should be more stable than CnF<sub>2</sub>.<ref name=VI>{{cite journal |last1=Hu |first1=Shu-Xian |last2=Zou |first2=Wenli |date=23 September 2021 |title=Stable copernicium hexafluoride (CnF<sub>6</sub>) with an oxidation state of VI+ |journal=Physical Chemistry Chemical Physics |volume=2022 |issue=24 |pages=321–325 |doi=10.1039/D1CP04360A|pmid=34889909 |bibcode=2021PCCP...24..321H }}</ref> In [[chemical polarity|polar]] solvents, copernicium is predicted to preferentially form the {{chem|CnF|5|-}} and {{chem|CnF|3|-}} anions rather than the analogous neutral fluorides (CnF<sub>4</sub> and CnF<sub>2</sub>, respectively), although the analogous bromide or iodide ions may be more stable towards [[hydrolysis]] in aqueous solution. The anions {{chem|CnCl|4|2-}} and {{chem|CnBr|4|2-}} should also be able to exist in aqueous solution.<ref name="Haire" /> The formation of thermodynamically stable copernicium(II) and (IV) fluorides would be analogous to the chemistry of xenon.<ref name="CRNL" /> Analogous to [[mercury(II) cyanide]] (Hg(CN)<sub>2</sub>), copernicium is expected to form a stable [[cyanide]], Cn(CN)<sub>2</sub>.<ref>{{cite journal |last1=Demissie |first1=Taye B. |last2=Ruud |first2=Kenneth |date=25 February 2017 |title=Darmstadtium, roentgenium, and copernicium form strong bonds with cyanide |journal=International Journal of Quantum Chemistry |volume=2017 |pages=e25393 |doi=10.1002/qua.25393|hdl=10037/13632|hdl-access=free }}</ref>
+Once copernicium is ionized, its chemistry may present several differences from those of zinc, cadmium, and mercury. Due to the stabilization of 7s electronic orbitals and destabilization of 6d ones caused by [[Relativistic quantum chemistry|relativistic effects]], Cn<sup>2+</sup> is likely to have a [Rn]5f<sup>14</sup>6d<sup>8</sup>7s<sup>2</sup> [[electronic configuration]], using the 6d orbitals before the 7s one, unlike its homologues. The fact that the 6d electrons participate more readily in chemical bonding means that once copernicium is ionized, it may behave more like a [[transition metal]] than its lighter [[Homologous series|homologues]], especially in the possible +4 oxidation state. In [[aqueous solution]]s, copernicium may form the +2 and perhaps +4 oxidation states.<ref name="Haire" /> The diatomic ion {{chem|Hg|2|2+}}, featuring mercury in the +1 oxidation state, is well-known, but the {{chem|Cn|2|2+}} ion is predicted to be unstable or even non-existent.<ref name="Haire" /> Copernicium(II) fluoride, CnF<sub>2</sub>, should be more unstable than the analogous mercury compound, [[mercury(II) fluoride]] (HgF<sub>2</sub>), and may even decompose spontaneously into its constituent elements. As the most electronegative reactive element, fluorine may be the only element able to oxidize copernicium even further to the +4 and even +6 oxidation states in CnF<sub>4</sub> and CnF<sub>6</sub>; the latter may require matrix-isolation conditions to be detected, as in the disputed detection of [[mercury(IV) fluoride|HgF<sub>4</sub>]]. CnF<sub>4</sub> should be more stable than CnF<sub>2</sub>.<ref name=VI>{{cite journal |last1=Hu |first1=Shu-Xian |last2=Zou |first2=Wenli |date=23 September 2021 |title=Stable copernicium hexafluoride (CnF<sub>6</sub>) with an oxidation state of VI+ |journal=Physical Chemistry Chemical Physics |volume=2022 |issue=24 |pages=321–325 |doi=10.1039/D1CP04360A|pmid=34889909 |bibcode=2021PCCP...24..321H }}</ref> In [[chemical polarity|polar]] solvents, copernicium is predicted to preferentially form the {{chem|CnF|5|-}} and {{chem|CnF|3|-}} anions rather than the analogous neutral fluorides (CnF<sub>4</sub> and CnF<sub>2</sub>, respectively), although the analogous bromide or iodide ions may be more stable towards [[hydrolysis]] in aqueous solution. The anions {{chem|CnCl|4|2-}} and {{chem|CnBr|4|2-}} should also be able to exist in aqueous solution.<ref name="Haire" /> The formation of thermodynamically stable copernicium(II) and (IV) fluorides would be analogous to the chemistry of xenon.<ref name="CRNL" /> Analogous to [[mercury(II) cyanide]] (Hg(CN)<sub>2</sub>), copernicium is expected to form a stable [[cyanide]], Cn(CN)<sub>2</sub>.<ref>{{cite journal |last1=Demissie |first1=Taye B. |last2=Ruud |first2=Kenneth |date=25 February 2017 |title=Darmstadtium, roentgenium, and copernicium form strong bonds with cyanide |journal=International Journal of Quantum Chemistry |volume=2017 |article-number=e25393 |doi=10.1002/qua.25393|hdl=10037/13632|hdl-access=free }}</ref>
 ===Physical and atomic===
 Copernicium should be a dense metal, with a [[density]] of 14.0&nbsp;g/cm<sup>3</sup> in the liquid state at 300&nbsp;K; this is similar to the known density of mercury, which is 13.534&nbsp;g/cm<sup>3</sup>. (Solid copernicium at the same temperature should have a higher density of 14.7&nbsp;g/cm<sup>3</sup>.) This results from the effects of copernicium's higher atomic weight being cancelled out by its larger interatomic distances compared to mercury.<ref name="CRNL" /> Some calculations predicted copernicium to be a gas at room temperature due to its closed-shell electron configuration,<ref name="Kratz">Kratz, Jens Volker. [https://tan11.jinr.ru/pdf/06_Sep/S_1/02_Kratz.pdf The Impact of Superheavy Elements on the Chemical and Physical Sciences] {{Webarchive|url=https://web.archive.org/web/20220614021708/http://tan11.jinr.ru/pdf/06_Sep/S_1/02_Kratz.pdf |date=14 June 2022 }}. 4th International Conference on the Chemistry and Physics of the Transactinide Elements, 5–11 September 2011, Sochi, Russia</ref> which would make it the first gaseous metal in the periodic table.<ref name="Haire" /><ref name="NS1975" /> A 2019 calculation agrees with these predictions on the role of relativistic effects, suggesting that copernicium will be a volatile liquid bound by [[dispersion forces]] under standard conditions. Its melting point is estimated at {{val|283|11|u=K}} and its boiling point at {{val|340|10|u=K}}, the latter in agreement with the experimentally estimated value of {{val|357|112|108|u=K}}.<ref name="CRNL" /> The atomic radius of copernicium is expected to be around 147&nbsp;pm. Due to the relativistic stabilization of the 7s orbital and destabilization of the 6d orbital, the Cn<sup>+</sup> and Cn<sup>2+</sup> ions are predicted to give up 6d electrons instead of 7s electrons, which is the opposite of the behavior of its lighter homologues.<ref name="Haire" />
-In addition to the relativistic contraction and binding of the 7s subshell, the 6d<sub>5/2</sub> orbital is expected to be destabilized due to [[spin–orbit coupling]], making it behave similarly to the 7s orbital in terms of size, shape, and energy. Predictions of the expected band structure of copernicium are varied. Calculations in 2007 expected that copernicium may be a [[semiconductor]]<ref name="Eichler">{{cite journal |last1=Eichler |first1=R. |last2=Aksenov |first2=N. V. |last3=Belozerov |first3=A. V. |last4=Bozhikov |first4=G. A. |last5=Chepigin |first5=V. I. |last6=Dmitriev |first6=S. N. |last7=Dressler |first7=R. |last8=Gäggeler |first8=H. W. |last9=Gorshkov |first9=A. V. | display-authors=8 |date=2008 |title=Thermochemical and physical properties of element 112 |journal=[[Angewandte Chemie]] |volume=47 |issue=17 |pages=3262–3266 |doi=10.1002/anie.200705019 |pmid=18338360}}</ref> with a [[band gap]] of around 0.2&nbsp;[[electronvolt|eV]],<ref name="hcp">{{cite journal |last1=Gaston |first1=Nicola |last2=Opahle |first2=Ingo |last3=Gäggeler |first3=Heinz W. |last4=Schwerdtfeger |first4=Peter |date=2007 |title=Is eka-mercury (element 112) a group 12 metal? |url=https://www.researchgate.net/publication/51380328 |journal=[[Angewandte Chemie]] |volume=46 |issue=10 |pages=1663–1666 |doi=10.1002/anie.200604262 |pmid=17397075 |access-date=5 November 2013}}</ref> crystallizing in the [[hexagonal close-packed]] [[crystal structure]].<ref name="hcp" /> However, calculations in 2017 and 2018 suggested that copernicium should be a [[noble metal]] at standard conditions with a [[body-centered cubic]] crystal structure: it should hence have no band gap, like mercury, although the density of states at the [[Fermi level]] is expected to be lower for copernicium than for mercury.<ref name="bcc">{{cite journal |last1=Gyanchandani |first1=Jyoti |last2=Mishra |first2=Vinayak |first3=G. K. |last3=Dey |first4=S. K. |last4=Sikka |date=January 2018 |title=Super heavy element Copernicium: Cohesive and electronic properties revisited |url=https://www.sciencedirect.com/science/article/pii/S0038109817303344 |journal=Solid State Communications |volume=269 |pages=16–22 |doi=10.1016/j.ssc.2017.10.009 |bibcode=2018SSCom.269...16G |access-date=28 March 2018|url-access=subscription }}</ref><ref>{{cite journal |last1=Čenčariková |first1=Hana |last2=Legut |first2=Dominik |year=2018 |title=The effect of relativity on stability of Copernicium phases, their electronic structure and mechanical properties |journal=Physica B |volume=536 |pages=576–582 |doi=10.1016/j.physb.2017.11.035 |bibcode=2018PhyB..536..576C |arxiv=1810.01955|s2cid=119100368 }}</ref> 2019 calculations then suggested that in fact copernicium has a large band gap of 6.4 ± 0.2&nbsp;eV, which should be similar to that of the noble gas [[radon]] (predicted as 7.1&nbsp;eV) and would make it an insulator; bulk copernicium is predicted by these calculations to be bound mostly by [[dispersion force]]s, like the noble gases.<ref name="CRNL" /> Like mercury, radon, and flerovium, but not [[oganesson]] (eka-radon), copernicium is calculated to have no [[electron affinity]].<ref>{{cite web |url=https://www.kernchemie.uni-mainz.de/downloads/che_7/presentations/borschevsky.pdf |title=Fully relativistic ''ab initio'' studies of superheavy elements |last1=Borschevsky |first1=Anastasia |first2=Valeria |last2=Pershina |first3=Uzi |last3=Kaldor |first4=Ephraim |last4=Eliav |website=www.kernchemie.uni-mainz.de |publisher=[[Johannes Gutenberg University Mainz]] |access-date=15 January 2018 |url-status=dead |archive-url=https://web.archive.org/web/20180115184921/https://www.kernchemie.uni-mainz.de/downloads/che_7/presentations/borschevsky.pdf |archive-date=15 January 2018}}</ref>
+In addition to the relativistic contraction and binding of the 7s subshell, the 6d<sub>5/2</sub> orbital is expected to be destabilized due to [[spin–orbit coupling]], making it behave similarly to the 7s orbital in terms of size, shape, and energy. Predictions of the expected band structure of copernicium are varied. Calculations in 2007 expected that copernicium may be a [[semiconductor]]<ref name="Eichler">{{cite journal |last1=Eichler |first1=R. |last2=Aksenov |first2=N. V. |last3=Belozerov |first3=A. V. |last4=Bozhikov |first4=G. A. |last5=Chepigin |first5=V. I. |last6=Dmitriev |first6=S. N. |last7=Dressler |first7=R. |last8=Gäggeler |first8=H. W. |last9=Gorshkov |first9=A. V. | display-authors=8 |date=2008 |title=Thermochemical and physical properties of element 112 |journal=[[Angewandte Chemie]] |volume=47 |issue=17 |pages=3262–3266 |doi=10.1002/anie.200705019 |pmid=18338360 |bibcode=2008ACIE...47.3262E }}</ref> with a [[band gap]] of around 0.2&nbsp;[[electronvolt|eV]],<ref name="hcp">{{cite journal |last1=Gaston |first1=Nicola |last2=Opahle |first2=Ingo |last3=Gäggeler |first3=Heinz W. |last4=Schwerdtfeger |first4=Peter |date=2007 |title=Is eka-mercury (element 112) a group 12 metal? |url=https://www.researchgate.net/publication/51380328 |journal=[[Angewandte Chemie]] |volume=46 |issue=10 |pages=1663–1666 |doi=10.1002/anie.200604262 |pmid=17397075 |bibcode=2007ACIE...46.1663G |access-date=5 November 2013}}</ref> crystallizing in the [[hexagonal close-packed]] [[crystal structure]].<ref name="hcp" /> However, calculations in 2017 and 2018 suggested that copernicium should be a [[noble metal]] at standard conditions with a [[body-centered cubic]] crystal structure: it should hence have no band gap, like mercury, although the density of states at the [[Fermi level]] is expected to be lower for copernicium than for mercury.<ref name="bcc">{{cite journal |last1=Gyanchandani |first1=Jyoti |last2=Mishra |first2=Vinayak |first3=G. K. |last3=Dey |first4=S. K. |last4=Sikka |date=January 2018 |title=Super heavy element Copernicium: Cohesive and electronic properties revisited |url=https://www.sciencedirect.com/science/article/pii/S0038109817303344 |journal=Solid State Communications |volume=269 |pages=16–22 |doi=10.1016/j.ssc.2017.10.009 |bibcode=2018SSCom.269...16G |access-date=28 March 2018|url-access=subscription }}</ref><ref>{{cite journal |last1=Čenčariková |first1=Hana |last2=Legut |first2=Dominik |year=2018 |title=The effect of relativity on stability of Copernicium phases, their electronic structure and mechanical properties |journal=Physica B |volume=536 |pages=576–582 |doi=10.1016/j.physb.2017.11.035 |bibcode=2018PhyB..536..576C |arxiv=1810.01955|s2cid=119100368 }}</ref> 2019 calculations then suggested that in fact copernicium has a large band gap of 6.4 ± 0.2&nbsp;eV, which should be similar to that of the noble gas [[radon]] (predicted as 7.1&nbsp;eV) and would make it an insulator; bulk copernicium is predicted by these calculations to be bound mostly by [[dispersion force]]s, like the noble gases.<ref name="CRNL" /> Like mercury, radon, and flerovium, but not [[oganesson]] (eka-radon), copernicium is calculated to have no [[electron affinity]].<ref>{{cite web |url=https://www.kernchemie.uni-mainz.de/downloads/che_7/presentations/borschevsky.pdf |title=Fully relativistic ''ab initio'' studies of superheavy elements |last1=Borschevsky |first1=Anastasia |first2=Valeria |last2=Pershina |first3=Uzi |last3=Kaldor |first4=Ephraim |last4=Eliav |website=www.kernchemie.uni-mainz.de |publisher=[[Johannes Gutenberg University Mainz]] |access-date=15 January 2018 |archive-url=https://web.archive.org/web/20180115184921/https://www.kernchemie.uni-mainz.de/downloads/che_7/presentations/borschevsky.pdf |archive-date=15 January 2018}}</ref>
 ==Experimental atomic gas phase chemistry==
 Interest in copernicium's chemistry was sparked by predictions that it would have the largest relativistic effects in the whole of period&nbsp;7 and group&nbsp;12, and indeed among all 118 known elements.<ref name="Haire" /> Copernicium is expected to have the ground state electron configuration [Rn] 5f<sup>14</sup> 6d<sup>10</sup> 7s<sup>2</sup> and thus should belong to group&nbsp;12 of the periodic table, according to the [[Aufbau principle]]. As such, it should behave as the heavier homologue of [[mercury (element)|mercury]] and form strong binary compounds with [[noble metal]]s like gold. Experiments probing the reactivity of copernicium have focused on the [[adsorption]] of atoms of element&nbsp;112 onto a gold surface held at varying temperatures, in order to calculate an adsorption enthalpy. Owing to relativistic stabilization of the 7s electrons, copernicium shows radon-like properties. Experiments were performed with the simultaneous formation of mercury and radon radioisotopes, allowing a comparison of adsorption characteristics.<ref name="superheavy" />
-The first chemical experiments on copernicium were conducted using the <sup>238</sup>U(<sup>48</sup>Ca,3n)<sup>283</sup>Cn reaction. Detection was by spontaneous fission of the claimed parent isotope with half-life of 5&nbsp;minutes. Analysis of the data indicated that copernicium was more volatile than mercury and had noble gas properties. However, the confusion regarding the synthesis of copernicium-283 has cast some doubt on these experimental results.<ref name="superheavy" /> Given this uncertainty, between April–May 2006 at the JINR, a FLNR–PSI team conducted experiments probing the synthesis of this isotope as a daughter in the nuclear reaction <sup>242</sup>Pu(<sup>48</sup>Ca,3n)<sup>287</sup>Fl.<ref name="superheavy" /> (The <sup>242</sup>Pu + <sup>48</sup>Ca fusion reaction has a slightly larger cross-section than the <sup>238</sup>U + <sup>48</sup>Ca reaction, so that the best way to produce copernicium for chemical experimentation is as an overshoot product as the daughter of flerovium.)<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=24–28 |isbn=9783642374661|date=2013}}</ref> In this experiment, two atoms of copernicium-283 were unambiguously identified and the adsorption properties were interpreted to show that copernicium is a more volatile homologue of mercury, due to formation of a weak metal-metal bond with gold.<ref name="superheavy" /> This agrees with general indications from some relativistic calculations that copernicium is "more or less" homologous to mercury.<ref>{{cite web |url=https://tan11.jinr.ru/pdf/07_Sep/S_3/04_Titov.pdf |title=Relativistic DFT and ab initio calculations on the seventh-row superheavy elements: E113 – E114 |last1=Zaitsevskii |first1=A. |first2=C. |last2=van Wüllen |first3=A. |last3=Rusakov |first4=A. |last4=Titov |date=September 2007 |website=jinr.ru |access-date=17 February 2018 |archive-date=18 February 2018 |archive-url=https://web.archive.org/web/20180218023915/http://tan11.jinr.ru/pdf/07_Sep/S_3/04_Titov.pdf |url-status=dead }}</ref> However, it was pointed out in 2019 that this result may simply be due to strong dispersion interactions.<ref name="CRNL" />
+The first chemical experiments on copernicium were conducted using the <sup>238</sup>U(<sup>48</sup>Ca,3n)<sup>283</sup>Cn reaction. Detection was by spontaneous fission of the claimed parent isotope with half-life of 5&nbsp;minutes. Analysis of the data indicated that copernicium was more volatile than mercury and had noble gas properties. However, the confusion regarding the synthesis of copernicium-283 has cast some doubt on these experimental results.<ref name="superheavy" /> Given this uncertainty, between April–May 2006 at the JINR, a FLNR–PSI team conducted experiments probing the synthesis of this isotope as a daughter in the nuclear reaction <sup>242</sup>Pu(<sup>48</sup>Ca,3n)<sup>287</sup>Fl.<ref name="superheavy" /> (The <sup>242</sup>Pu + <sup>48</sup>Ca fusion reaction has a slightly larger cross-section than the <sup>238</sup>U + <sup>48</sup>Ca reaction, so that the best way to produce copernicium for chemical experimentation is as an overshoot product as the daughter of flerovium.)<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=24–28 |isbn=978-3-642-37466-1|date=2013}}</ref> In this experiment, two atoms of copernicium-283 were unambiguously identified and the adsorption properties were interpreted to show that copernicium is a more volatile homologue of mercury, due to formation of a weak metal-metal bond with gold.<ref name="superheavy" /> This agrees with general indications from some relativistic calculations that copernicium is "more or less" homologous to mercury.<ref>{{cite web |url=https://tan11.jinr.ru/pdf/07_Sep/S_3/04_Titov.pdf |title=Relativistic DFT and ab initio calculations on the seventh-row superheavy elements: E113 – E114 |last1=Zaitsevskii |first1=A. |first2=C. |last2=van Wüllen |first3=A. |last3=Rusakov |first4=A. |last4=Titov |date=September 2007 |website=jinr.ru |access-date=17 February 2018 |archive-date=18 February 2018 |archive-url=https://web.archive.org/web/20180218023915/http://tan11.jinr.ru/pdf/07_Sep/S_3/04_Titov.pdf }}</ref> However, it was pointed out in 2019 that this result may simply be due to strong dispersion interactions.<ref name="CRNL" />
 In April 2007, this experiment was repeated and a further three atoms of copernicium-283 were positively identified. The adsorption property was confirmed and indicated that copernicium has adsorption properties in agreement with being the heaviest member of group 12.<ref name="superheavy">
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