Group 12 element

Group 12 in the periodic table
Name by element	zinc group
CAS group number; (US, pattern A-B-A)	IIB
old IUPAC number; (Europe, pattern A-B)	IIB
↓ Period
4	Zinc (Zn); 30 Transition metal
5	Cadmium (Cd); 48 Transition metal
6	Mercury (Hg); 80 Transition metal
7	Copernicium (Cn); 112 transition metal
	primordial element
	synthetic element
	Atomic number color:
	green=liquid, black=solid

Group 12, by modern IUPAC numbering,^[1] is a group of chemical elements in the periodic table. It includes zinc (Zn), cadmium (Cd), mercury (Hg),^[2]^[3]^[4] and copernicium (Cn).^[5] Formerly this group was named IIB (pronounced as "group two B", as the "II" is a Roman numeral) by CAS and old IUPAC system.^{[note 1]}

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,^{[note 2]} 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.

^ Fluck, E. (1988). "New Notations in the Periodic Table" (PDF). Pure Appl. Chem. 60 (3): 431–436. doi:10.1351/pac198860030431. S2CID 96704008. Retrieved 24 March 2012.
^ Greenwood & Earnshaw 1997.
^ Cotton et al. 1999.
^ Housecroft, C. E.; Sharpe, A. G. (2008). Inorganic Chemistry (3rd ed.). Prentice Hall. ISBN 978-0-13-175553-6.
^ Eichler, R.; Aksenov, N. V.; Belozerov, A. V.; Bozhikov, G. A.; Chepigin, V. I.; Dmitriev, S. N.; Dressler, R.; Gäggeler, H. W.; Gorshkov, V. A.; Haenssler, F.; et al. (2007). "Chemical Characterization of Element 112". Nature. 447 (7140): 72–75. Bibcode:2007Natur.447...72E. doi:10.1038/nature05761. PMID 17476264. S2CID 4347419.
^ Simmons, L. M. (December 1947). "A modification of the periodic table". Journal of Chemical Education. 24 (12): 588. Bibcode:1947JChEd..24..588S. doi:10.1021/ed024p588.
^ Mewes, J.-M.; Smits, O. R.; Kresse, G.; Schwerdtfeger, P. (2019). "Copernicium is a Relativistic Noble Liquid". Angewandte Chemie International Edition. 58 (50): 17964–17968. doi:10.1002/anie.201906966. PMC 6916354. PMID 31596013.

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[1] Fluck, E. (1988). "New Notations in the Periodic Table" (PDF). Pure Appl. Chem. 60 (3): 431–436. doi:10.1351/pac198860030431. S2CID 96704008. Retrieved 24 March 2012.

[FOOTNOTEGreenwoodEarnshaw1997-2] Greenwood & Earnshaw 1997.

[FOOTNOTECottonWilkinsonMurilloBochmann1999-3] Cotton et al. 1999.

[4] Housecroft, C. E.; Sharpe, A. G. (2008). Inorganic Chemistry (3rd ed.). Prentice Hall. ISBN 978-0-13-175553-6.

[07Ei01-5] Eichler, R.; Aksenov, N. V.; Belozerov, A. V.; Bozhikov, G. A.; Chepigin, V. I.; Dmitriev, S. N.; Dressler, R.; Gäggeler, H. W.; Gorshkov, V. A.; Haenssler, F.; et al. (2007). "Chemical Characterization of Element 112". Nature. 447 (7140): 72–75. Bibcode:2007Natur.447...72E. doi:10.1038/nature05761. PMID 17476264. S2CID 4347419.

[6] Simmons, L. M. (December 1947). "A modification of the periodic table". Journal of Chemical Education. 24 (12): 588. Bibcode:1947JChEd..24..588S. doi:10.1021/ed024p588.

[CRNL-8] Mewes, J.-M.; Smits, O. R.; Kresse, G.; Schwerdtfeger, P. (2019). "Copernicium is a Relativistic Noble Liquid". Angewandte Chemie International Edition. 58 (50): 17964–17968. doi:10.1002/anie.201906966. PMC 6916354. PMID 31596013.

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