Editing Group 12 element (section)

{{short description|Group of chemical elements}}
{{Good article}}
{{Infobox periodic table group
| title       = Group&nbsp;12 {{nowrap|in the periodic table}}
| group number= 12
| trivial name=
| by element  = zinc group
| CAS         = IIB
| old IUPAC   = IIB
| mark        = Zn,Cd,Hg,Cn
| left        = [[Group 11 element|group 11]]
| right       = [[boron group]]}}
{| class="floatright"
! colspan=2 style="text-align:left;" | ↓&nbsp;<small>[[Period (periodic table)|Period]]</small>
|-
! [[Period 4 element|4]]
| {{element cell image|30|Zinc|Zn| |Solid|Transition metal|Primordial|image=Zinc fragment sublimed and 1cm3 cube.jpg|image caption=Zinc, fragment and sublimed 99.995%}}
|-
! [[Period 5 element|5]]
| {{element cell image|48|Cadmium|Cd| |Solid|Transition metal|Primordial|image=Cadmium-crystal bar.jpg|image caption=Cadmium, crystal bar 99.99%}}
|-
! [[Period 6 element|6]]
| {{element cell image|80|Mercury|Hg| |Liquid|Transition metal|link=Mercury (element)|Primordial|image=Pouring liquid mercury bionerd.jpg|image caption=Mercury, liquid}}
|-
! [[Period 7 element|7]]
| {{element cell image|112|Copernicium|Cn| |Unknown phase|Transition metal|Synthetic|legend=transition metal}}
|-
| colspan="2"|
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''Legend''
{| style="text-align:center; border:0; margin:1em auto;"
|-
| style="border:{{element color|Primordial}}; background:{{Element color|table mark}}; padding:0 2px;" | [[primordial element]]
|-
| style="border:{{element color|Synthetic}}; background:{{Element color|table mark}}; padding:0 2px;" | [[synthetic element]]
|}
|}

'''Group 12''', by modern [[Group (periodic table)#CAS and old IUPAC numbering (A/B)|IUPAC]] numbering,<ref>{{cite journal |last1=Fluck |first1=E. |year=1988 |title=New Notations in the Periodic Table |journal=[[Pure and Applied Chemistry|Pure Appl. Chem.]] |volume=60 |pages=431–436 |doi=10.1351/pac198860030431 |url=http://www.iupac.org/publications/pac/1988/pdf/6003x0431.pdf |access-date=24 March 2012 |issue=3 |s2cid=96704008 }}</ref> is a [[Periodic table group|group]] of [[chemical element]]s in the [[periodic table group|periodic table]]. It includes [[zinc]] (Zn), [[cadmium]] (Cd), [[Mercury (element)|mercury]] (Hg),{{sfn|Greenwood|Earnshaw|1997|p=}}{{sfn|Cotton|Wilkinson|Murillo|Bochmann|1999|p=}}<ref>{{Housecroft3rd}}</ref> and [[copernicium]] (Cn).<ref name=07Ei01>{{cite journal |title=Chemical Characterization of Element 112 |journal=[[Nature (journal)|Nature]]|year=2007|volume=447|pages=72–75 |doi=10.1038/nature05761 |pmid=17476264 |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=V. A. |last10=Haenssler |first10=F. |last11=Itkis |first11=M. G. |last12=Laube |first12=A. |last13=Lebedev |first13=V. Ya. |last14=Malyshev |first14=O. N. |last15=Oganessian |first15=Yu. Ts. |last16=Petrushkin |first16=O. V. |last17=Piguet |first17=D. |last18=Rasmussen |first18=P. |last19=Shishkin |first19=S. V. |last20=Shutov |first20=A. V. |last21=Svirikhin |first21=A. I. |last22=Tereshatov |first22=E. E. |last23=Vostokin |first23=G. K. |last24=Wegrzecki |first24=M. |last25=Yeremin |first25=A. V. |display-authors=10 |issue=7140 |bibcode=2007Natur.447...72E|s2cid=4347419}}</ref> Formerly this group was named ''IIB'' (pronounced as "group two B", as the "II" is a [[Roman numeral]]) by [[Group (periodic table)#CAS and old IUPAC numbering (A/B)|CAS]] and old IUPAC system.{{refn|The name '''volatile metals''' for group 12 has occasionally been used,<ref>{{cite journal |last1=Simmons |first1=L. M. |date=December 1947 |title=A modification of the periodic table |journal=Journal of Chemical Education |volume=24 |issue=12 |pages=588 |doi=10.1021/ed024p588 |bibcode=1947JChEd..24..588S}}</ref> although this much more commonly refers to any metal having a high [[volatility (chemistry)|volatility]].|group=note}}

The three group 12 elements that occur naturally are zinc, cadmium and mercury. They are all widely used in electric and electronic applications, as well as in various alloys. The first two members of the group share similar properties as they are solid metals under standard conditions. Mercury is the only [[metal]] that is known to be a liquid at room temperature – as copernicium's boiling point has not yet been measured accurately enough,{{refn|group=note|refn={{val|340|10|u=K}} predicted, {{val|357|112|108|u=K}} experimentally<ref name=CRNL>{{cite journal |last1=Mewes |first1=J.-M. |last2=Smits |first2=O. R. |last3=Kresse |first3=G. |last4=Schwerdtfeger |first4=P. |title=Copernicium is a Relativistic Noble Liquid |journal=Angewandte Chemie International Edition  |date=2019 |volume=58 |issue=50 |pages=17964–17968 |doi=10.1002/anie.201906966 |pmid=31596013 |pmc=6916354 |url=https://www.researchgate.net/publication/336389017}}</ref>}} it is not yet known whether it is a liquid or a gas under standard conditions. While zinc is very important in the biochemistry of living organisms, cadmium and mercury are both highly toxic. As copernicium does not occur in nature, it has to be synthesized in the laboratory.

Due to their complete [[Electron shell|d-shell]] they are sometimes excluded from the [[transition metal]]s.