Editing Copernicium (section)

==Predicted properties==
Very few properties of copernicium or its compounds have been measured; this is due to its extremely limited and expensive production<ref name="Bloomberg-Copernicium">{{Cite news|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]]|date=28 August 2019|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 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 (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.

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>

===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>