Editing Zinc (section)

==Compounds and chemistry==
{{Main|Zinc compounds}}

===Reactivity===
{{see also|Clemmensen reduction}}
Zinc has an [[electron configuration]] of [Ar]4s<sup>2</sup>3d<sup>10</sup> and is a member of the [[group 12 element|group 12]] of the [[periodic table]]. It is a moderately reactive [[metal]] and strong [[reducing agent]];<ref name="CRC2006p8-29">{{harvnb|CRC|2006|pp='''8'''–29}}</ref> in the [[reactivity series]] it is comparable to [[manganese]].<ref>{{cite video|first1=John&nbsp;W.|last1=Moore|first2=Lynn&nbsp;R.|last2=Hunsberger|first3=Steven&nbsp;D.|last3=Gammon|first4=Kelly|last4=Houston&nbsp;Jetzer|orig-date=6 Mar 2012|year=2022|title=Reaction of zinc with iodine|url=https://www.chemedx.org/video/reaction-zinc-iodine|type=web video|publisher=American Chemical Society, Division of Chemical Education|via=ChemEdX}}</ref>   The surface of the pure metal [[tarnish]]es quickly, eventually forming a protective [[Passivation (chemistry)|passivating]] layer of the basic [[Hydrozincite|zinc carbonate]], {{chem|Zn|5|(OH)|6|(CO<sub>3</sub>)|2}}, by reaction with atmospheric [[carbon dioxide]].<ref>{{Cite book|publisher=CRC Press|date=1994|page=121|isbn=978-0-8247-9213-8|title=Corrosion Resistance of Zinc and Zinc Alloys| first=Frank C.|last=Porter}}</ref>

Zinc burns in air with a bright bluish-green flame, giving off fumes of [[zinc oxide]].<ref name="Holl" /> Zinc reacts readily with [[acid]]s, [[alkali]]s and other non-metals.<ref>{{Cite book|last=Hinds|first=John Iredelle Dillard|title=Inorganic Chemistry: With the Elements of Physical and Theoretical Chemistry|publisher=John Wiley & Sons|location=New York|date=1908|edition=2nd|pages=506–508|url=https://books.google.com/books?id=xMUMAAAAYAAJ}}</ref> Extremely pure zinc reacts only slowly at [[room temperature]] with acids.<ref name="Holl" /> Strong acids, such as [[hydrochloric acid|hydrochloric]] or [[sulfuric acid]], can remove the passivating layer and the subsequent reaction with the acid releases hydrogen gas.<ref name="Holl" />

Zinc chemistry resembles that of the late first-row transition metals, [[nickel]] and copper,<ref name="Greenwood1997p1206" /> as well as certain [[main group element]]s.  Almost all zinc compounds have the element in the +2 [[oxidation state]].<ref name=GenChem>{{Cite book|last=Brady|first=James E.|author2=Humiston, Gerard E.|author3=Heikkinen, Henry|title=General Chemistry: Principles and Structure|publisher=John Wiley & Sons|date=1983|edition=3rd|page=[https://archive.org/details/generalchemistry1982brad/page/671 671]|isbn=978-0-471-86739-5|url=https://archive.org/details/generalchemistry1982brad/page/671}}</ref>  When Zn<sup>2&plus;</sup> compounds form, the outer [[electron shell|shell]] ''s'' electrons are lost, yielding a bare zinc ion with the electronic configuration [Ar]3d<sup>10</sup>.<ref>{{Cite book|last=Ritchie|first=Rob|title=Chemistry|publisher=Letts and Lonsdale|date=2004|edition=2nd|page=71|isbn=978-1-84315-438-9|url=https://books.google.com/books?id=idT9j6406gsC}}</ref> The filled interior ''d'' shell generally does not participate in bonding, producing [[diamagnetic]] and mostly colorless compounds.<ref name="Greenwood1997p1206" /> In aqueous solution an octahedral complex, {{chem|[Zn(H|2|O)<sub>6</sub>]|2+}} is the predominant species.<ref>{{Cite book|last=Burgess|first=John|title=Metal ions in solution|publisher=Ellis Horwood|location=New York|date=1978|page=147|isbn=978-0-470-26293-1}}</ref> 

The [[ionic radii]] of zinc and magnesium happen to be nearly identical. Consequently some of the equivalent salts have the same [[crystal structure]],<ref>{{harvnb|CRC|2006|pp='''12'''–11–12}}</ref> and in other circumstances where ionic radius is a determining factor, the chemistry of zinc has much in common with that of magnesium.<ref name="Holl">{{Cite book|publisher=Walter de Gruyter|date=1985|edition=91–100| pages=1034–1041|isbn=978-3-11-007511-3|title=Lehrbuch der Anorganischen Chemie|first1=Arnold F.|last1=Holleman|last2=Wiberg|first2=Egon|last3=Wiberg|first3=Nils|language=de|chapter=Zink}}</ref> Compared to the transition metals, zinc tends to form bonds with a greater degree of [[covalency]].  [[Complex (chemistry)|Complexes]] with [[nitrogen|N]]- and [[sulfur|S]]- donors are much more stable.<ref name="Greenwood1997p1206">{{harvnb|Greenwood|Earnshaw|1997|p=1206}}</ref> Complexes of zinc are mostly 4- or 6- [[coordinate covalent bond|coordinate]], although 5-coordinate complexes are known.<ref name="Holl" />

Other oxidation states require unusual physical conditions, and the only positive oxidation states demonstrated are +1 or +2.<ref name=GenChem/>  The [[volatilization]] of zinc in combination with zinc chloride at temperatures above 285&nbsp;°C indicates the formation of {{chem|Zn|2|Cl|2}}, a zinc compound with a +1 oxidation state.<ref name="Holl" /> Calculations indicate that a zinc compound with the oxidation state of +4 is unlikely to exist.<ref>{{Cite journal|journal=Inorganic Chemistry|date=1994|volume=33|issue=10|pages=2122–2131|title=Oxidation state +IV in group 12 chemistry. Ab initio study of zinc(IV), cadmium(IV), and mercury(IV) fluorides|author=Kaupp M.|author2=Dolg M.|author3=Stoll H.|author4=Von Schnering H. G.|doi=10.1021/ic00088a012|url=https://nbn-resolving.org/urn:nbn:de:bvb:20-opus-60018}}</ref> Zn(III) is predicted to exist in the presence of strongly electronegative trianions;<ref>{{cite journal |last1=Samanta |first1=Devleena |last2=Jena |first2=Puru |title=Zn in the +III Oxidation State |url=https://pubs.acs.org/doi/abs/10.1021/ja3029119# |journal=Journal of the American Chemical Society |date=2012|volume=134 |issue=20 |pages=8400–8403 |doi=10.1021/ja3029119 |pmid=22559713 |arxiv=1201.1014 |bibcode=2012JAChS.134.8400S }}</ref><ref>{{cite journal |last1=Fang |first1=Hong |last2=Banjade |first2=Huta |last3=Deepika |last4=Jena |first4=Puru |title=Realization of the Zn3+ oxidation state |journal=Nanoscale |date=2021|volume=13 |issue=33 |pages=14041–14048 |doi=10.1039/D1NR02816B |pmid=34477685 |s2cid=237400349 |doi-access=free }}</ref> however, there exists some doubt around this possibility.<ref>{{cite journal |last1=Schlöder |first1=Tobias |display-authors=etal |title=Can Zinc Really Exist in Its Oxidation State +III? |url=https://pubs.acs.org/doi/10.1021/ja3052409# |journal=Journal of the American Chemical Society |date=2012|volume=134 |issue=29 |pages=11977–11979 |doi=10.1021/ja3052409 |pmid=22775535 |bibcode=2012JAChS.13411977S }}</ref>

===Zinc(I) compounds===
Zinc(I) compounds are very rare. The [Zn<sub>2</sub>]<sup>2+</sup> ion is implicated by the formation of a yellow diamagnetic glass by dissolving metallic zinc in molten ZnCl<sub>2</sub>.<ref>{{Housecroft3rd|page=739–741, 843}}</ref> The [Zn<sub>2</sub>]<sup>2+</sup> core would be analogous to the [Hg<sub>2</sub>]<sup>2+</sup> cation present in [[mercury (element)|mercury]](I) compounds. The [[diamagnetism|diamagnetic]] nature of the ion confirms its dimeric structure. The first zinc(I) compound containing the Zn–Zn bond, [[Decamethyldizincocene|(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)<sub>2</sub>Zn<sub>2</sub>]] has been reported in 2004.<ref name="ResaCarmona">{{cite journal |author1=Resa, I. |author2=Carmona, E. |author3=Gutierrez-Puebla, E. |author4=Monge, A. | title = Decamethyldizincocene, a Stable Compound of Zn(I) with a Zn-Zn Bond | journal = [[Science (journal)|Science]] | doi = 10.1126/science.1101356 | pmid = 15326350 | year = 2004 | volume = 305 | issue = 5687 | pages = 1136–8|bibcode=2004Sci...305.1136R |s2cid=38990338 }}</ref>

===Zinc(II) compounds===
[[File:Zinc acetate.JPG|thumb|left|[[Zinc acetate]], {{chem|Zn|(|C|H|3|C|O|2|)|2}}|alt=Sheets of zinc acetate formed by slow evaporation]]
[[File:Zinc chloride.jpg|thumb|Zinc chloride|alt=White lumped powder on a glass plate]]
[[Binary compound]]s of zinc are known for most of the [[metalloid]]s and all the [[Nonmetal (chemistry)|nonmetal]]s except the [[noble gas]]es. The oxide [[zinc oxide|ZnO]] is a white powder that is nearly insoluble in neutral aqueous solutions, but is [[amphoteric]], dissolving in both strong basic and acidic solutions.<ref name="Holl" /> The other [[chalcogen]]ides ([[zinc sulfide|ZnS]], [[zinc selenide|ZnSe]], and [[zinc telluride|ZnTe]]) have varied applications in electronics and optics.<ref>{{cite web|url=http://www.americanelements.com/znsu.html|title=Zinc Sulfide|publisher=[[American Elements]]|access-date=February 3, 2009|url-status=live|archive-url=https://archive.today/20120717190353/http://www.americanelements.com/znsu.html|archive-date=July 17, 2012}}</ref> [[Pnictogenide]]s ([[Zinc nitride|{{chem|Zn|3|N|2}}]], [[zinc phosphide|{{chem|Zn|3|P|2}}]], [[zinc arsenide|{{chem|Zn|3|As|2}}]] and [[zinc antimonide|{{chem|Zn|3|Sb|2}}]]),<ref>{{cite book|title=Academic American Encyclopedia|url=https://books.google.com/books?id=YgI4E7w5JI8C|date=1994|publisher=Grolier Inc.| location=[[Danbury, Connecticut]] |isbn=978-0-7172-2053-3|page=202}}</ref><ref>{{cite web|url=http://www.americanelements.com/znp.html|title=Zinc Phosphide|publisher=[[American Elements]]|access-date=February 3, 2009|url-status=live|archive-url=https://archive.today/20120717120313/http://www.americanelements.com/znp.html|archive-date=July 17, 2012}}</ref> the peroxide ([[zinc peroxide|{{chem|ZnO|2}}]]), the hydride ([[zinc hydride|{{chem|ZnH|2}}]]), and the carbide ({{chem|ZnC|2}}) are also known.<ref>{{Cite journal|journal=Diamond and Related Materials|volume=9|date=2000|title=Peculiarities of interaction in the Zn–C system under high pressures and temperatures |issue=2|vauthors=Shulzhenko AA, Ignatyeva IY, Osipov AS, Smirnova TI |doi=10.1016/S0925-9635(99)00231-9|pages=129–133|bibcode = 2000DRM.....9..129S }}</ref> Of the four [[halide]]s, [[zinc fluoride|{{chem|ZnF|2}}]] has the most ionic character, while the others ([[zinc chloride|{{chem|ZnCl|2}}]], [[zinc bromide|{{chem|ZnBr|2}}]], and [[zinc iodide|{{chem|ZnI|2}}]]) have relatively low melting points and are considered to have more covalent character.<ref name="Greenwood1997p1211">{{harvnb|Greenwood|Earnshaw|1997|p=1211}}</ref>

In weak basic solutions containing {{chem|Zn|2+}} ions, the hydroxide [[Zinc hydroxide|{{chem|Zn(OH)|2}}]] forms as a white [[precipitate]]. In stronger alkaline solutions, this hydroxide is dissolved to form zincates ([[zincate|{{chem|[Zn||(OH)<sub>4</sub>]|2-}}]]).<ref name="Holl" /> The nitrate [[Zinc nitrate|{{chem|Zn(NO<sub>3</sub>)|2}}]], chlorate [[Zinc chlorate|{{chem|Zn(ClO<sub>3</sub>)|2}}]], sulfate [[Zinc sulfate|{{chem|ZnSO|4}}]], phosphate [[Zinc phosphate|{{chem|Zn|3|(PO<sub>4</sub>)|2}}]], molybdate [[Zinc molybdate|{{chem|ZnMoO|4}}]], cyanide [[Zinc cyanide|{{chem|Zn(CN)|2}}]], arsenite {{chem|Zn(AsO<sub>2</sub>)|2}}, arsenate {{chem|Zn(AsO<sub>4</sub>)|2|·8H|2|O}} and the chromate [[Zinc chromate|{{chem|ZnCrO|4}}]] (one of the few colored zinc compounds) are a few examples of other common inorganic compounds of zinc.<ref>{{Cite journal| last=Rasmussen| first=J. K.| author2=Heilmann, S. M.| title=In situ Cyanosilylation of Carbonyl Compounds: O-Trimethylsilyl-4-Methoxymandelonitrile| journal=Organic Syntheses, Collected Volume| volume=7| page=521| date=1990| url=http://www.orgsyn.org/orgsyn/prep.asp?prep=cv7p0521| url-status=live| archive-url=https://web.archive.org/web/20070930230236/http://www.orgsyn.org/orgsyn/prep.asp?prep=cv7p0521| archive-date=September 30, 2007| df=mdy-all}}</ref><ref name="perry">{{Cite book|title=Handbook of Inorganic Compounds|last=Perry|first=D. L.|pages=448–458|date=1995|isbn=978-0-8493-8671-8|publisher=CRC Press}}</ref>

[[Organozinc compound]]s are those that contain zinc–[[carbon]] covalent bonds. Diethylzinc ([[Diethylzinc|{{chem|(C|2|H<sub>5</sub>)|2|Zn}}]]) is a reagent in synthetic chemistry. It was first reported in 1848 from the reaction of zinc and [[ethyl iodide]], and was the first compound known to contain a metal–carbon [[sigma bond]].<ref>{{Cite journal|title=On the isolation of the organic radicals|author=Frankland, E.|journal=Quarterly Journal of the Chemical Society|date=1850|volume=2|issue=3|page=263|doi=10.1039/QJ8500200263|url=https://zenodo.org/record/1861200|author-link=Edward Frankland}}</ref>

===Test for zinc===

Cobalticyanide paper (Rinnmann's test for Zn) can be used as a chemical indicator for zinc. 4&nbsp;g of K<sub>3</sub>Co(CN)<sub>6</sub> and 1&nbsp;g of KClO<sub>3</sub> is dissolved on 100&nbsp;ml of water. Paper is dipped in the solution and dried at 100&nbsp;°C. One drop of the sample is dropped onto the dry paper and heated. A green disc indicates the presence of zinc.<ref>{{Cite book|title=CRC- Handbook of Chemistry and Physics|last=Lide|first=David|publisher=CRC press|year=1998|isbn=978-0-8493-0479-8|pages=Section 8 Page 1}}</ref>

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