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Revision as of 13:53, 15 February 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Saving copy of the {{chembox}} taken from revid 476304083 of page Zinc_chloride for the Chem/Drugbox validation project (updated: 'ChEMBL').		Latest revision as of 22:12, 1 January 2025 edit Keresluna (talk | contribs)Autopatrolled, Extended confirmed users4,071 edits →Uses: +
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			{{Short description|Chemical compound}}
	{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}}
			{{For|the battery type|Zinc–chloride battery}}
	{{chembox		{{chembox
	| Verifiedfields = changed		| Verifiedfields = changed
			| Watchedfields = changed
	| verifiedrevid = 470636078
			| verifiedrevid = 477004315
	| Name = Zinc chloride		| Name = Zinc chloride
	| ImageFile = Zinc chloride.jpg		| ImageFile = Zinc chloride anhydrous.jpg
			| ImageCaption = Anhydrous
	| ImageSize = 200px
	| ImageName = Zinc chloride hydrate		| ImageFile1 = Zinc chloride.jpg
			| ImageName1 = Zinc chloride hydrate
	| ImageFile1 = Kristallstruktur Zinkchlorid.png
			| ImageCaption1 = Monohydrate
			| ImageFile2 = Kristallstruktur Zinkchlorid.png
	| IUPACName = Zinc chloride		| IUPACName = Zinc chloride
	| OtherNames = Zinc(II) chloride<br/>Zinc dichloride<br/>Butter of zinc		| OtherNames = {{ubl|Butter of zinc|Neutral zinc chloride (1:2)|Zinc bichloride (archaic)|Zinc(II) chloride}}
	| Section1 = {{Chembox Identifiers		|Section1={{Chembox Identifiers
			| CASNo = 7646-85-7
			| CASNo_Ref = {{cascite|correct|CAS}}
			| CASNo_Comment = Anhydrous
			| CASNo1_Ref = {{cascite|changed|??}}
			| CASNo1 = 29426-92-4
			| CASNo1_Comment = Tetrahydrate
			| CASNo2_Ref = {{cascite|changed|??}}
			| CASNo2 = 21351-91-7
			| CASNo2_Comment = Mixed hydrate
	| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}		| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| ChemSpiderID = 5525		| ChemSpiderID = 5525
	| UNII_Ref = {{fdacite|correct|FDA}}		| ChEMBL_Ref = {{ebicite|correct|EBI}}
	| UNII = 86Q357L16B		| ChEMBL = 1200679
			| DrugBank = DB14533
	| ChEMBL_Ref = {{ebicite|changed|EBI}}
	| ChEMBL = <!-- blanked - oldvalue: 1200679 -->
	| InChI = 1/2ClH.Zn/h2*1H;/q;;+2/p-2
	| InChIKey = JIAARYAFYJHUJI-NUQVWONBAB
	| ChEBI_Ref = {{ebicite|correct|EBI}}		| ChEBI_Ref = {{ebicite|correct|EBI}}
	| ChEBI = 49976		| ChEBI = 49976
			| PubChem = 3007855
			| RTECS = ZH1400000
			| EINECS = 231-592-0
			| UNII_Ref = {{fdacite|correct|FDA}}
			| UNII = 86Q357L16B
			| UNNumber = 2331
	| SMILES = ClCl		| SMILES = ClCl
	| StdInChI_Ref = {{stdinchicite|correct|chemspider}}		| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
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	| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}		| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
	| StdInChIKey = JIAARYAFYJHUJI-UHFFFAOYSA-L		| StdInChIKey = JIAARYAFYJHUJI-UHFFFAOYSA-L
			| InChI = 1/2ClH.Zn/h2*1H;/q;;+2/p-2
	| CASNo = 7646-85-7
			| InChIKey = JIAARYAFYJHUJI-NUQVWONBAB
	| CASNo_Ref = {{cascite|correct|CAS}}
	| PubChem = 3007855
	| RTECS = ZH1400000
	| EINECS = 231-592-0
	| UNNumber = 2331
	| ATCCode_prefix = B05
	| ATCCode_suffix = XA12
	}}		}}
	| Section2 = {{Chembox Properties		|Section2={{Chembox Properties
	| Formula = ZnCl<sub>2</sub>		| Formula = {{chem2|ZnCl2}}
	| MolarMass = 136.315 g/mol		| MolarMass = 136.315 g/mol
	| Appearance = white crystalline solid <br> ]		| Appearance = White ] and very ] crystalline solid
	| Odor = odorless		| Odor = odorless
	| Density = 2.907 g/cm<sup>3</sup>		| Density = 2.907 g/cm<sup>3</sup>
	| Solubility = 4320 g/L (25 °C)		| Solubility = 432.0 g/100 g (25 °C)<br>615 g/100 g (100 °C)
	| MeltingPtC = 292		| MeltingPtC = 290
			| MeltingPt_ref = <ref name=Merck>{{cite book | author = O'Neil, M. J. | title = The Merck index : an encyclopedia of chemicals, drugs, and biologicals | publisher = Whitehouse Station | location = N. J. | year = 2001 | isbn = 978-0-911910-13-1 | display-authors = etal | url-access = registration | url = https://archive.org/details/merckindexency00onei }}</ref>
	| BoilingPtC = 756
	| Solvent1 = alcohol		| BoilingPtC = 732
			| BoilingPt_ref = <ref name=Merck />
	| Solubility1 = 4300 g/L
			| Solvent1 = ethanol
			| Solubility1 = 430.0 g/100 ml
	| SolubleOther = soluble in ], ] and ]		| SolubleOther = soluble in ], ] and ]
			| MagSus = −65.0·10<sup>−6</sup> cm<sup>3</sup>/mol
	}}		}}
	| Section3 = {{Chembox Structure		|Section3={{Chembox Structure
	| Coordination =], linear in the gas phase		| Coordination =], linear in the gas phase
	| CrystalStruct =		| CrystalStruct =
	}}		}}
	| Section7 = {{Chembox Hazards		|Section6={{Chembox Pharmacology
			| ATCCode_prefix = B05
	| ExternalMSDS =
			| ATCCode_suffix = XA12
	| EUClass = Harmful ('''Xn''')<br/>Corrosive ('''C''')<br/>Dangerous for the environment ('''N''')
			}}
	| EUIndex = 030-003-00-2
			|Section7={{Chembox Hazards
	| RPhrases = {{R22}}, {{R34}}, {{R50/53}}
			| MainHazards= Oral toxicity, irritant<ref>{{Cite web|url=https://www.sigmaaldrich.com/US/en/sds/sigald/208086?userType=undefined |title=Zinc chloride safety data sheet |publisher=] |access-date=May 21, 2024 |date=March 2, 2024}}</ref>
	| SPhrases = {{S1/2}}, {{S26}}, {{S36/37/39}}, {{S45}}, {{S60}}, {{S61}}
			| ExternalSDS =
			| GHSPictograms = {{GHS05}}{{GHS07}}{{GHS09}}
			| GHSSignalWord = Danger
			| HPhrases = {{H-phrases|302|314|410}}
			| PPhrases = {{P-phrases|273|280|301+330+331|305+351+338|308+310}}
	| NFPA-H = 3		| NFPA-H = 3
	| NFPA-F = 0		| NFPA-F = 0
	| NFPA-R = 0		| NFPA-R = 0
			| LD50 = {{ubl|350 mg/kg (rat, oral)|350 mg/kg (mouse, oral)|200 mg/kg (guinea pig, oral)|1100 mg/kg (rat, oral)|1250 mg/kg (mouse, oral)}}<ref name=IDLH/>
	| LD50 = 350 mg/kg, rat (oral)
			| IDLH = 50 mg/m<sup>3</sup> (fume)<ref name=PGCH>{{PGCH|0674}}</ref>
			| LC50 = 1260 mg/m<sup>3</sup> (rat, 30 min)<br />1180 mg-min/m<sup>3</sup><ref name=IDLH>{{IDLH|7646857|Zinc chloride fume}}</ref>
			| REL = TWA 1 mg/m<sup>3</sup> ST 2 mg/m<sup>3</sup> (fume)<ref name=PGCH/>
			| PEL = TWA 1 mg/m<sup>3</sup> (fume)<ref name=PGCH/>
	}}		}}
	| Section8 = {{Chembox Other		|Section8={{Chembox Related
	| OtherAnions = ]<br/>]<br/>]		| OtherAnions = {{ubl|]|]|]}}
	| OtherCations = ]<br/>]		| OtherCations = {{ubl|]|]}}
	}}		}}
	}}		}}
			'''Zinc chloride''' is an ] ] with the ] ZnCl<sub>2</sub>·''n''H<sub>2</sub>O, with ''n'' ranging from 0 to 4.5, forming ]. Zinc chloride, anhydrous and its hydrates, are colorless or white ] solids, and are highly ] in ]. Five hydrates of zinc chloride are known, as well as four forms of anhydrous zinc chloride.<ref name="a"/>
			All forms of zinc chloride are ] and are produced by the reaction of zinc or its compounds with some form of ]. This compound is a ], readily forming complexes. Zinc chloride finds wide application in ] processing, ], chemical synthesis of ], such as ], and processes to produce other compounds of zinc.<ref name="a" />
			==History==
			Zinc chloride has long been known but currently practiced industrial applications all evolved in the latter half of 20th century.<ref name="a"/>
			An ] ] formed from aqueous zinc chloride and ] was first investigated in 1855 by ]. Sorel later went on to investigate the related ], which bears his name.<ref>{{cite book |author1=Wilson, A. D. |author2=Nicholson, J. W. | year = 1993 | title = Acid-Base Cements: Their Biomedical and Industrial Applications | publisher = Cambridge University Press | isbn = 978-0-521-37222-0 }}</ref>
			Dilute aqueous zinc chloride was used as a disinfectant under the name "Burnett's Disinfecting Fluid".<ref>{{cite book | author = Watts, H. | year = 1869 | title = A Dictionary of Chemistry and the Allied Branches of Other Sciences | publisher = Longmans, Green | url = https://archive.org/details/adictionarychem11wattgoog }}</ref> From 1839 ] promoted its use as a disinfectant as well as a wood preservative. The Royal Navy conducted trials into its use as a disinfectant in the late 1840s, including during the ]; and at the same time experiments were conducted into its preservative properties as applicable to the shipbuilding and railway industries. Burnett had some commercial success with his eponymous fluid. Following his death however, its use was largely superseded by that of ] and other proprietary products.<ref>{{cite journal |last1=McLean |first1=David |title=Protecting wood and killing germs: 'Burnett's Liquid' and the origins of the preservative and disinfectant industries in early Victorian Britain |journal=Business History |date=April 2010 |volume=52 |issue=2 |pages=285–305|doi=10.1080/00076791003610691 |s2cid=154790730 }}</ref>
			==Structure and properties==
			Unlike other metal dichlorides, zinc dichloride forms several crystalline forms (]s). Four forms are known: α, β, γ, and δ. Each form features tetrahedral {{chem2|Zn(2+)}} centers surrounded by chloride ions.<ref name=Wells>{{cite book | author = Wells, A. F. | year = 1984 | title = Structural Inorganic Chemistry | location = Oxford | publisher = Clarendon Press | isbn = 978-0-19-855370-0 }}</ref>
			{|class="wikitable" style="text-align:center"
			|-
			! Form !! ] !! ] !! ] !! ] !! ] (nm) !!　''b'' (nm) !! ''c'' (nm) !! ''Z'' !! ] (g/cm<sup>3</sup>)
			|-
			| α || ] || tI12 || I{{overline|4}}2d || 122 || 0.5398 || 0.5398 || 0.64223 || 4 || 3.00
			|-
			| β || tetragonal || tP6 || P4<sub>2</sub>/nmc || 137 || 0.3696 || 0.3696 || 1.071 || 2 || 3.09
			|-
			| γ || ] || mP36 || P2<sub>1</sub>/c || 14 || 0.654 || 1.131 || 1.23328 || 12 || 2.98
			|-
			| δ || ] || oP12 || Pna2<sub>1</sub> || 33 || 0.6125 || 0.6443 || 0.7693 || 4 || 2.98
			|}
			Here ''a'', ''b'', and ''c'' are lattice constants, ''Z'' is the number of structure units per unit cell, and ρ is the density calculated from the structure parameters.<ref>{{cite journal | last1 = Oswald | first1 = H. R. | last2 = Jaggi | first2 = H. | title = Zur Struktur der wasserfreien Zinkhalogenide I. Die wasserfreien Zinkchloride | journal = Helvetica Chimica Acta | year = 1960 | volume = 43 | issue = 1 | pages = 72–77 | doi = 10.1002/hlca.19600430109 }}</ref><ref>{{cite journal | last1 = Brynestad | first1 = J. | last2 = Yakel | first2 = H. L. | title = Preparation and Structure of Anhydrous Zinc Chloride | journal = Inorganic Chemistry | year = 1978 | volume = 17 | issue = 5 | pages = 1376–1377 | doi = 10.1021/ic50183a059 }}</ref><ref>{{cite journal | last1 = Brehler | first1 = B. | title = Kristallstrukturuntersuchungen an ZnCl<sub>2</sub> | journal = Zeitschrift für Kristallographie | year = 1961 | volume = 115 | issue = 5–6 | pages = 373–402 | doi = 10.1524/zkri.1961.115.5-6.373 | bibcode = 1961ZK....115..373B }}</ref>
			The orthorhombic form (δ) rapidly changes to one of the other forms on exposure to the atmosphere. A possible explanation is that the {{chem2|OH−}} ions originating from the absorbed water facilitate the rearrangement.<ref name=Wells/> Rapid cooling of molten {{chem2|ZnCl2}} gives a ].<ref>{{cite journal |author1=Mackenzie, J. D. |author2=Murphy, W. K. | title = Structure of Glass-Forming Halides. II. Liquid Zinc Chloride | journal = The Journal of Chemical Physics | year = 1960 | volume = 33 | issue = 2 | pages = 366–369 | doi = 10.1063/1.1731151 |bibcode=1960JChPh..33..366M }}</ref>
			Molten {{chem2|ZnCl2}} has a high viscosity at its melting point and a comparatively low electrical conductivity, which increases markedly with temperature.<ref name = "prince">{{cite book | author = Prince, R. H. | year = 1994 | title = Encyclopedia of Inorganic Chemistry | editor = King, R. B. | publisher = John Wiley & Sons | isbn = 978-0-471-93620-6 }}</ref><ref>{{cite book | author = Ray, H. S. | year = 2006| title = Introduction to Melts: Molten Salts, Slags and Glasses | publisher = Allied Publishers | isbn = 978-81-7764-875-1 }}</ref> As indicated by a ] study, the viscosity is explained by the presence of polymers,.<ref>{{cite book | author = Danek, V. | year = 2006 | title = Physico-Chemical Analysis of Molten Electrolytes | publisher = Elsevier | isbn = 978-0-444-52116-3 }}</ref> ] study indicated the presence of tetrahedral {{chem2|ZnCl4}} centers, which requires aggregation of {{chem2|ZnCl2}} monomers as well.<ref>{{cite journal | last1 = Price | first1 = D. L. | last2 = Saboungi | first2 = M.-L. | last3 = Susman | first3 = S. | last4 = Volin | first4 = K. J. | last5 = Wright | first5 = A. C. | title = Neutron Scattering Function of Vitreous and Molten Zinc Chloride | journal = Journal of Physics: Condensed Matter | year = 1991 | volume = 3 | issue = 49 | pages = 9835–9842 | doi = 10.1088/0953-8984/3/49/001 | bibcode = 1991JPCM....3.9835P | s2cid = 250902741 }}</ref>
			===Hydrates===
			Various hydrates of zinc chloride are known: {{chem2|ZnCl2(H2O)_{''n''}|}} with ''n'' = 1, 1.33, 2.5, 3, and 4.5.<ref name=Holleman>{{cite book |author1=Holleman, A. F. |author2=Wiberg, E. | title = Inorganic Chemistry | publisher = Academic Press | location = San Diego | year = 2001 | isbn = 978-0-12-352651-9 }}</ref> The 1.33-hydrate, previously thought to be the hemitrihydrate, consists of ''trans''-Zn(H<sub>2</sub>O)<sub>4</sub>Cl<sub>2</sub> centers with the chlorine atoms connected to repeating ZnCl<sub>4</sub> chains. The hemipentahydrate, structurally formulated , consists of Zn(H<sub>2</sub>O)<sub>5</sub>Cl octahedrons where the chlorine atom is part of a <sup>2-</sup> tetrahedera. The trihydrate consists of distinct hexaaquozinc(II) cations and ] anions; formulated . Finally, the heminonahydrate, structurally formulated ·3H<sub>2</sub>O also consists of distinct hexaaquozinc(II) cations and tetrachlorozincate anions like the trihydrate but has three extra water molecules. These different hydrates can be produced by evaporation of aqueous solutions of zinc chloride at different temperatures.<ref name="1.33">{{cite journal |author1=H. Follner |author2=B. Brehler |title=Die Kristallstruktur des ZnCl2.4/3H2O |journal=Acta Crystallographica B |date=1970 |volume=26 |issue=11 |pages=1679–1682 |doi=10.1107/S0567740870004715 |bibcode=1970AcCrB..26.1679F |trans-title=The crystal structure of ZnCl2.4/3H2O |language=de}}</ref><ref name="hydrcrys">{{cite journal |author1=E. Hennings |author2=H. Schmidt |author3=W. Voigt |title=Crystal structures of ZnCl2·2.5H2O, ZnCl2·3H2O and ZnCl2·4.5H2O |journal=Acta Crystallographica E |date=2014 |volume=70 |issue=12 |pages=515–518 |doi=10.1107/S1600536814024738 |pmid=25552980 |language=en|pmc=4257420 }}</ref>
			==Preparation and purification==
			Historically, zinc chlorides are prepared from the reaction of ] with zinc metal or zinc oxide. Aqueous acids cannot be used to produce anhydrous zinc chloride. According to an early procedure, a suspension of powdered zinc in ] is treated with hydrogen chloride, followed by drying<ref>{{cite journal |doi=10.1039/JR9320002282 |title=Notes: The Preparation of Pure Zinc Chloride |date=1932 |last1=Hamilton |first1=R. T. |last2=Butler |first2=J. A. V. |journal=Journal of the Chemical Society (Resumed) |pages=2283–4 }}</ref> The overall method remains useful in industry, but without the solvent:<ref name="a" />
			: {{chem2|Zn + 2 HCl → ZnCl2 + H2}}
			Aqueous solutions may be readily prepared similarly by treating Zn metal, zinc carbonate, zinc oxide, and ] with hydrochloric acid:<ref>{{cite book |doi=10.1002/0471238961.2609140307151504.a02.pub3 |chapter=Zinc Compounds |title=Kirk-Othmer Encyclopedia of Chemical Technology |date=2017 |first1=Frank E. |last1=Goodwin |pages=9–10 |isbn=978-0-471-23896-6 }}</ref>
			: {{chem2|ZnS + 2 HCl + 4 H2O → ZnCl2(H2O)4 + H2S}}
			Hydrates can be produced by evaporation of an aqueous solution of zinc chloride. The temperature of the evaporation determines the hydrates For example, evaporation at room temperature produces the 1.33-hydrate.<ref name="1.33" /><ref name="old">{{cite journal |author1=F. Mylius |author2=R. Dietz |title=Über das Chlorzink. (Studien über die Löslichkeit der Salze XIV.) |journal=Zeitschrift für anorganische Chemie |date=1905 |volume=44 |issue=1 |pages=209–220 |doi=10.1002/zaac.19050440115 |language=en}}</ref> Lower evaporation temperatures produce higher hydrates.<ref name="hydrcrys" />
			Commercial samples of zinc chloride typically contain water and products from hydrolysis as impurities. Laboratory samples may be purified by ] from hot ]. Anhydrous samples can be purified by ] in a stream of ] gas, followed by heating the sublimate to 400&nbsp;°C in a stream of dry ] gas.<ref name="eros">{{cite journal |doi=10.1002/047084289X.rz007.pub3|title=Zinc chloride|author=Glenn J. McGarvey Jean-François Poisson Sylvain Taillemaud|year=2016|journal=Encyclopedia of Reagents for Organic Synthesis|pages=1–20|isbn=978-0-470-84289-8}}</ref> A simple method relies on treating the zinc chloride with ].<ref>{{cite book | author = Pray, A. P. | title=Anhydrous Metal Chlorides|series = Inorganic Syntheses | year = 1990 | volume = 28 | pages = 321–322}}</ref>
			==Reactions==
			===Chloride complexes===
			A number of salts containing the ] anion, {{chem2|(2−)}}, are known.<ref name = "prince"/> "Caulton's reagent", {{chem2|]2Cl3(])6] }}, which is used in organic chemistry, is an example of a salt containing {{chem2|(2−)}}.<ref>{{cite book | volume = 3 |editor1=Mulzer, J. |editor2=Waldmann, H. | title = Organic Synthesis Highlights | year = 1998 | publisher = Wiley-VCH | isbn = 978-3-527-29500-5 }}</ref><ref>{{cite journal | last1 = Bouma | first1 = R. J. | last2 = Teuben | first2 =J. H. | last3 = Beukema | first3 = W. R. | last4 = Bansemer | first4 = R. L. | last5 = Huffman | first5 = J. C. | last6 = Caulton | first6 = K. G. | title = Identification of the Zinc Reduction Product of VCl<sub>3</sub> · 3THF as <nowiki></nowiki><sub>2</sub><nowiki></nowiki> | journal = Inorganic Chemistry | year = 1984 | volume = 23 | issue = 17 | pages = 2715–2718 | doi = 10.1021/ic00185a033 }}</ref> The compound {{chem2|]3ZnCl5}} contains ] {{chem2|(2−)}} and ] anions,<ref name=Wells/> so, the compound is not caesium pentachlorozincate, but caesium tetrachlorozincate chloride. No compounds containing the {{chem2|(4−)}} ion (hexachlorozincate ion) have been characterized.<ref name=Wells/> The compound {{chem2|ZnCl2*0.5HCl*H2O}} crystallizes from a solution of {{chem2|ZnCl2}} in ]. It contains a polymeric anion {{chem2|(Zn2Cl5−)_{''n''}|}} with balancing monohydrated ] ions, {{chem2|H5O2+}} ions.<ref name=Wells/><!--<ref>{{cite book | author-link = Joseph William Mellor | author = Mellow, J. W. | year = 1946 | title = A Comprehensive Treatise on Inorganic and Theoretical Chemistry | publisher = Longmans, Green }}</ref>-->
			===Adducts===
			]
			The adduct with thf {{chem2|ZnCl2(thf)2}} illustrates the tendency of zinc chloride to form 1:2 adducts with weak ]s. Being soluble in ethers and lacking acidic protons, this complex is used in the synthesis of ]s.<ref>{{cite journal |doi=10.1002/zaac.19976230163 |title=Difluorenylzink als Alkylierungsmittel zur Darstellung von Triorganometallanen der 13. Gruppe. Synthese und Kristallstruktur von &#91;GaFl<sub>3</sub>(THF)&#93; · Toluol (Fl = Fluorenyl) |date=1997 |last1=Dashti |first1=Anahita |last2=Niediek |first2=Katharina |last3=Werner |first3=Bert |last4=Neumüller |first4=Bernhard |journal=Zeitschrift für Anorganische und Allgemeine Chemie |volume=623 |issue=1–6 |pages=394–402 }}</ref> A related 1:2 complex is {{chem2|ZnCl2(NH2OH)2}} (zinc dichloride di(hydroxylamine)). Known as Crismer's salt, this complexes releases ] upon heating.<ref>{{cite book |doi=10.1002/9780470132401.ch2|chapter=Dichlorobis(hydroxylamine)zinc(II) (Crismer's Salt)|year=1967|volume=9|last1=Walker|first1=John E.|last2=Howell|first2=David M.|title=Inorganic Syntheses|pages=2–3|isbn=978-0-470-13240-1}}</ref> The distinctive ability of aqueous solutions of {{chem2|ZnCl2}} to dissolve ] is attributed to the formation of zinc-cellulose complexes, illustrating the stability of its adducts.<ref>{{cite journal |author1=Xu, Q. |author2=Chen, L.-F. | title = Ultraviolet Spectra and Structure of Zinc-Cellulose Complexes in Zinc Chloride Solution | journal = Journal of Applied Polymer Science | year = 1999 | volume = 71 | issue = 9 | pages = 1441–1446 | doi = 10.1002/(SICI)1097-4628(19990228)71:9<1441::AID-APP8>3.0.CO;2-G }}</ref> Cellulose also dissolves in molten {{chem2|ZnCl2}} hydrate.<ref>{{cite journal | last1 = Fischer | first1 = S. | last2 = Leipner | first2 = H. | last3 = Thümmler | first3 = K. | last4 = Brendler | first4 = E. | last5 = Peters | first5 = J. | title = Inorganic Molten Salts as Solvents for Cellulose | journal = Cellulose | year = 2003 | volume = 10 | issue = 3 | pages = 227–236 | doi = 10.1023/A:1025128028462 | s2cid = 92194004 }}</ref> Overall, this behavior is consistent with Zn<sup>2+</sup> as a ] Lewis acid.
			When solutions of zinc chloride are treated with ], diverse ] complexes are produced. In addition to the tetrahedral 1:2 complex {{chem2|ZnCl2(NH3)2}}.<ref>{{cite journal | last1 = Yamaguchi | first1 = T. | last2 = Lindqvist | first2 = O. | title = The Crystal Structure of Diamminedichlorozinc(II), ZnCl<sub>2</sub>(NH<sub>3</sub>)<sub>2</sub>. A New Refinement | journal = Acta Chemica Scandinavica A | year = 1981 | volume = 35 | issue = 9 | pages = 727–728 | doi = 10.3891/acta.chem.scand.35a-0727 | url = http://actachemscand.org/pdf/acta_vol_35a_p0727-0728.pdf | doi-access = free }}</ref><ref>{{cite book | author = Vulte, H. T. | title = Laboratory Manual of Inorganic Preparations | publisher = Read Books | year = 2007 | isbn = 978-1-4086-0840-1 }}</ref>
			the complex {{chem2|Zn(NH3)4Cl2*H2O}} also has been isolated. The latter contains the {{chem2|(2+)}} ion,.<ref name=Wells/> The species in aqueous solution have been investigated and show that {{chem2|(2+)}} is the main species present with {{chem2|+}} also present at lower {{chem2|NH3}}:Zn ratio.<ref>{{cite journal | last1 = Yamaguchi | first1 = T. | last2 = Ohtaki | first2 = H. | title = X-Ray Diffraction Studies on the Structures of Tetraammine- and Triamminemonochlorozinc(II) Ions in Aqueous Solution | journal = Bulletin of the Chemical Society of Japan | year = 1978 | volume = 51 | issue = 11 | pages = 3227–3231 | doi = 10.1246/bcsj.51.3227 | doi-access = free }}</ref>
			===Aqueous solutions of zinc chloride===
			Zinc chloride dissolves readily in water to give {{chem2|ZnCl_{''x''}(H2O)_{4−''x''}|}} species and some free chloride.<ref>{{cite journal | last1 = Irish | first1 = D. E. | last2 = McCarroll | first2 = B. | last3 = Young | first3 = T. F. | title = Raman Study of Zinc Chloride Solutions | journal = The Journal of Chemical Physics | year = 1963 | volume = 39 | issue = 12 | pages = 3436–3444 | doi = 10.1063/1.1734212 | bibcode = 1963JChPh..39.3436I }}</ref><ref>{{cite journal | last1 = Yamaguchi | first1 = T. | last2 = Hayashi | first2 = S. | last3 = Ohtaki | first3 = H. | title = X-Ray Diffraction and Raman Studies of Zinc(II) Chloride Hydrate Melts, ZnCl<sub>2</sub> · ''R'' H<sub>2</sub>O (''R'' = 1.8, 2.5, 3.0, 4.0, and 6.2) | journal = The Journal of Physical Chemistry | year = 1989 | volume = 93 | issue = 6 | pages = 2620–2625 | doi = 10.1021/j100343a074 }}</ref><ref>{{cite journal |author1=Pye, C. C. |author2=Corbeil, C. R. |author3=Rudolph, W. W. | title = An ''ab initio'' Investigation of Zinc Chloro Complexes | journal = Physical Chemistry Chemical Physics | year = 2006 | volume = 8 | issue = 46 | pages = 5428–5436 | doi = 10.1039/b610084h | issn = 1463-9076 | pmid = 17119651 |bibcode=2006PCCP....8.5428P |s2cid=37521287 }}</ref> Aqueous solutions of {{chem2|ZnCl2}} are acidic: a 6&nbsp;] aqueous solution has a ] of 1.<ref name=Holleman/> The acidity of aqueous {{chem2|ZnCl2}} solutions relative to solutions of other Zn<sup>2+</sup> salts (say the sulfate) is due to the formation of the tetrahedral chloro ]es such as <sup>-</sup>.<ref>{{cite book |author = Brown, I. D. | year = 2006 | title = The Chemical Bond in Inorganic Chemistry: The Bond Valence Model | publisher = Oxford University Press | isbn = 978-0-19-929881-5 }}</ref> Most metal dichlorides for octahedral complexes, with stronger O-H bonds. The combination of hydrochloric acid and {{chem2|ZnCl2}} gives a reagent known as "]". Such reagents were once used a ] for primary alcohols. Similar reactions are the basis of industrial routes from methanol and ethanol respectively to ] and ].<ref>{{cite journal |author1=Kjonaas, R. A. |author2=Riedford, B. A. | title = A Study of the Lucas Test | journal = Journal of Chemical Education | year = 1991 | volume = 68 | issue = 8 | pages = 704 | doi = 10.1021/ed068p704 |bibcode=1991JChEd..68..704K }}</ref>
			In alkali solution, zinc chloride converts to various zinc hydroxychlorides. These include {{chem2|(2−)}}, {{chem2|(2−)}}, {{chem2|(2−)}}, and the insoluble {{chem2|Zn5(OH)8Cl2*H2O}}. The latter is the mineral ].<ref>{{cite book | author = Zhang, X. G. | year = 1996 | title = Corrosion and Electrochemistry of Zinc | publisher = Springer | isbn = 978-0-306-45334-2 }} {{cite web |url=http://webmineral.com/data/Simonkolleite.shtml#.VEA-9SLF-vM |title= Simonkolleite Mineral Data |author=Staff writer(s)|website= webmineral.com |access-date= October 16, 2014}}</ref> When zinc chloride hydrates are heated, HCl gas evolves and hydroxychlorides result.<ref>{{cite journal |author1=Feigl, F. |author2=Caldas, A. | title = Some Applications of Fusion Reactions with Zinc Chloride in Inorganic Spot Test Analysis | journal = Microchimica Acta | year = 1956 | volume = 44 | issue = 7–8 | pages = 1310–1316 | doi = 10.1007/BF01257465 |s2cid=96823985 }}</ref>
			In aqueous solution {{chem2|ZnCl2}}, as well as other halides (bromide, iodide), behave interchangeably for the preparation of other zinc compounds. These salts give
			precipitates of zinc carbonate when treated with aqueous carbonate sources:<ref name="a" />
			:{{chem2|ZnCl2 + Na2CO3 → ZnCO3 + 2 NaCl}}
			] reacts with ]s and ]s to form a colored compound "Ruhemann's purple" (RP). Spraying with a zinc chloride solution, which is colorless, forms a 1:1 complex RP:{{chem2|ZnCl(H2O)2}}, which is more readily detected as it fluoresces more intensely than RP.<ref>{{cite book | author = Menzel, E. R. | year = 1999 | title = Fingerprint Detection with Lasers | publisher = CRC Press | isbn = 978-0-8247-1974-6 }}</ref>
			===Redox===
			Anhydrous zinc chloride melts and even boils without any decomposition up to 900&nbsp;°C. When zinc metal is dissolved in molten {{chem2|ZnCl2}} at 500–700&nbsp;°C, a yellow diamagnetic solution is formed consisting of the {{chem2|Zn2(2+)}}, which has zinc in the oxidation state +1. The nature of this dizinc dication has been confirmed by ].<ref name="Holleman"/> Although {{chem2|Zn2(2+)}} is unusual, mercury, a heavy congener of zinc, forms a wide variety of {{chem2|Hg2(2+)}} salts.
			In the presence of oxygen, zinc chloride oxidizes to ] above 400&nbsp;°C. Again, this observation indicates the nonoxidation of Zn<sup>2+</sup>.<ref name="decomp">{{cite journal |author1=Frida Jones |author2=Honghi Tran |author3=Daniel Lindberg |author4=Liming Zhao |author5=Mikko Hupa |title=Thermal Stability of Zinc Compounds |journal=Energy & Fuels |date=2013 |volume=27 |issue=10 |pages=5663–5669 |doi=10.1021/ef400505u |language=en}}</ref>
			===Zinc hydroxychloride===
			Concentrated aqueous zinc chloride dissolves ] to form zinc hydroxychloride, which is obtained as colorless crystals:<ref>{{cite book|author1=F. Wagenknecht|author2=R. Juza|chapter=Zinc Hydroxychloride|title=Handbook of Preparative Inorganic Chemistry, 2nd Ed. |editor=G. Brauer|publisher=Academic Press|year=1963|place=NY,NY|volume=2pages=1071}}</ref>
			:{{chem2|ZnCl2 + ZnO + H2O -> 2 ZnCl(OH)}}
			The same material forms when hydrated zinc chloride is heated.<ref>{{cite book | author = House, J. E. | year = 2008 | title = Inorganic Chemistry | publisher = Academic Press | isbn = 978-0-12-356786-4 }}</ref>
			The ability of zinc chloride to dissolve metal oxides (MO)<ref name="HOWI">{{cite book|last=Wiberg|first=Nils|title=Lehrbuch der Anorganischen Chemie |trans-title=Holleman & Wiberg, Textbook of Inorganic chemistry |language=de|publisher=de Gruyter, Berlin|year=2007 |page = 1491|isbn=978-3-11-017770-1}}</ref> is relevant to the utility of {{chem2|ZnCl2}} as a ] for ]. It dissolves ] oxides, exposing the clean metal surface.<ref name="HOWI"/><!--Fluxes with {{chem2|ZnCl2}} as an active ingredient are sometimes called "tinner's fluid".{{Citation needed|date=June 2024}}
			...of the idealized formula {{chem2|MZnOCl2}}.{{Additional citation needed|date=October 2017|reason=Suggested reaction is bit dubious and it is not mentioned in some major chemistry textbooks (or anywhere else that I could find).}}-->
			==Organic syntheses with zinc chloride==
			Zinc chloride is an occasional laboratory reagent often as a ]. A dramatic example is the conversion of methanol into ] using zinc chloride as the solvent and catalyst:<ref name = HMB>{{cite journal|title = Hydrocarbons from Methanol|first = Clarence D.|last = Chang|pages = 1–118|doi = 10.1080/01614948308078874|journal = ]|volume = 25|issue = 1|year = 1983}}</ref>
			:{{chem2|15 CH3OH → C6(CH3)6 + 3 CH4 + 15 H2O}}
			This kind of reactivity has been investigated for the valorization of C1 precursors.<ref>{{cite journal|title = Onium Ylide chemistry. 1. Bifunctional acid-base-catalyzed conversion of heterosubstituted methanes into ethylene and derived hydrocarbons. The onium ylide mechanism of the C<sub>1</sub> → C<sub>2</sub> conversion|first1 = George A.|last1 = Olah|first2 = Hans|last2 = Doggweiler|first3 = Jeff D.|last3 = Felberg|first4 = Stephan|last4 = Frohlich|first5 = Mary Jo|last5 = Grdina|first6 = Richard|last6 = Karpeles|first7 = Takashi|last7 = Keumi|first8 = Shin-ichi|last8 = Inaba|first9 = Wai M.|last9 = Ip|first10 = Koop|last10 = Lammertsma|first11 = George|last11 = Salem|first12 = Derrick|last12 = Tabor|journal = ]|year = 1984|volume = 106|issue = 7|pages = 2143–2149|doi = 10.1021/ja00319a039}}</ref>
			Examples of zinc chloride as a Lewis acid include the ]:<ref>{{OrgSynth | last1 = Shriner | first1 = R. L. | last2 = Ashley | first2 = W. C. | last3 = Welch | first3 = E. | title = 2-Phenylindole | year = 1942 | volume = 22 | pages = 98 | collvol = 3 |collvolpages = 725 | doi = 10.15227/orgsyn.022.00981955 | prep = cv3p0725 }}</ref>
			:]
			Related Lewis-acid behavior is illustrated by a traditional preparation of the dye ] from ] and ], which involves a ].<ref>{{cite book | author = Furnell, B. S. | title = Vogel's Textbook of Practical Organic Chemistry | edition = 5th | publisher = Longman/Wiley | location = New York | year = 1989 }}</ref> This transformation has in fact been accomplished using even the hydrated {{chem2|ZnCl2}} sample shown in the picture above. Many examples describe the use of zinc chloride in ] reactions.<ref>{{OrgSynth | last = Cooper | first = S. R. | title = Resacetophenone | collvol = 3 | collvolpages = 761 | prep = cv3p0761 | year = 1941 | volume = 21 | pages = 103 | doi = 10.15227/orgsyn.021.0103 }}</ref><ref>{{cite journal | last1 = Dike | first1 = S. Y. | last2 = Merchant | first2 = J. R. | last3 = Sapre | first3 = N. Y. | title = A New and Efficient General Method for the Synthesis of 2-Spirobenzopyrans: First Synthesis of Cyclic Analogues of Precocene I and Related Compounds | journal = ] | year = 1991 | volume = 47 | issue = 26 | pages = 4775–4786 | doi = 10.1016/S0040-4020(01)86481-4 }}</ref>
			]
			Zinc chloride also activates ] and ] halides towards substitution by weak ]s such as ]s:<ref>{{cite journal |author1=Bauml, E. |author2=Tschemschlok, K. |author3=Pock, R. |author4=Mayr, H. | title = Synthesis of γ-Lactones from Alkenes Employing p-Methoxybenzyl Chloride as <sup>+</sup>CH<sub>2</sub>-CO<sub>2</sub><sup>−</sup> Equivalent | journal = Tetrahedron Letters | year = 1988 | volume = 29 | issue = 52 | pages = 6925–6926 | doi = 10.1016/S0040-4039(00)88476-2 | url = http://epub.ub.uni-muenchen.de/3799/1/086.pdf }}</ref>
			]
			In similar fashion, {{chem2|ZnCl2}} promotes selective }}]] reduction of tertiary, allylic or benzylic halides to the corresponding hydrocarbons.<ref name="eros" />
			Zinc ]s, prepared from alkali metal enolates and {{chem2|ZnCl2}}, provide control of ] in ] reactions. This control is attributed to ] at the zinc. In the example shown below, the '']'' product was favored over the '']'' by a factor of 5:1 when {{chem2|ZnCl2}}.<ref>{{cite journal |author1=House, H. O. |author2=Crumrine, D. S. |author3=Teranishi, A. Y. |author4=Olmstead, H. D. | title = Chemistry of Carbanions. XXIII. Use of Metal Complexes to Control the Aldol Condensation | journal = Journal of the American Chemical Society | year = 1973 | volume = 95 | issue = 10 | pages = 3310–3324 | doi = 10.1021/ja00791a039 }}</ref>
			]
			===Organozinc precursor===
			Being inexpensive and anhydrous, ZnCl<sub>2</sub> is a widely used for the synthesis of many ] reagents, such as those used in the palladium catalyzed ] with ]s or ]s. The prominence of this reaction was highlighted by the award of the 2010 ] to ].<ref>{{cite journal |doi=10.1002/anie.201101380 |title=Magical Power of Transition Metals: Past, Present, and Future (Nobel Lecture) |date=2011 |last1=Negishi |first1=Ei-Ichi |journal=Angewandte Chemie International Edition |volume=50 |issue=30 |pages=6738–6764 |pmid=21717531 }}</ref>
			]
			], a highly reactive form of zinc metal, is generated by reduction of zinc dichloride with ]. Rieke Zn is useful for the preparation of ]s<ref>{{cite journal|author1=Chen, T.-A. |author2=Wu, X. |author3=Rieke, R. D. |title=Regiocontrolled Synthesis of Poly(3-alkylthiophenes) Mediated by Rieke Zinc: Their Characterization and Solid-State Properties|journal=Journal of the American Chemical Society |year=1995|volume=117|pages=233–244|doi=10.1021/ja00106a027}}</ref> and for the ].<ref>{{cite journal|author1=Rieke, R. D. |author2=Hanson, M. V. |title= New Organometallic Reagents Using Highly Reactive Metals| journal=Tetrahedron|year= 1997|volume= 53|pages=1925–1956| doi=10.1016/S0040-4020(96)01097-6|issue=6}}</ref>
			==Uses==
			===Industrial organic chemistry===
			Zinc chloride is used as a catalyst or reagent in diverse reactions conducted on an industrial scale. Benzaldehyde, 20,000 tons of which is produced annually in Western countries, is produced from inexpensive ] by exploiting the catalytic properties of zinc dichloride. This process begins with the chlorination of toluene to give ]. In the presence of a small amount of anhydrous zinc chloride, a mixture of benzal chloride are treated continuously with water according to the following stoichiometry:<ref>{{cite book |doi=10.1002/14356007.a03_463.pub2 |chapter=Benzaldehyde |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2011 |last1=Brühne |first1=Friedrich |last2=Wright |first2=Elaine |isbn=978-3-527-30385-4 }}</ref>
			:{{chem2|C6H5CHCl2 + H2O -> C6H5CHO + 2 HCl}}
			Similarly zinc chloride is employed in hydrolysis of benzotrichloride, the main route to ]. It serves as a catalyst for the production of methylene-bis(dithiocarbamate).<ref name="a">{{Ullmann | author1=Dieter M. M. Rohe | author2=Hans Uwe Wolf | title=Zinc Compounds | year=2007 | pages=1–6 | doi=10.1002/14356007.a28_537|.pub2}}</ref>
			===As a metallurgical flux===
			The use of zinc chloride as a flux, sometimes in a mixture with ] (see also ]), involves the production of HCl and its subsequent reaction with surface oxides.
			Zinc chloride forms two salts with ammonium chloride: {{chem2|2}} and {{chem2|3Cl}}, which decompose on heating liberating HCl, just as zinc chloride hydrate does. The action of zinc chloride/ammonium chloride fluxes, for example, in the ] process produces {{chem2|H2}} gas and ammonia fumes.<ref>{{cite book | title = ASM handbook | year = 1990 | author = American Society for Metals | publisher = ASM International | isbn = 978-0-87170-021-6 }}</ref>
			===Other uses===
			Relevant to its affinity for these paper and textiles, {{chem2|ZnCl2}} is used as a fireproofing agent and in the process of making ], which is made by soaking paper in concentrated zinc chloride.<ref>{{cite journal |author1=Yiqun Fang |author2=Aojing Xue |author3=Fengqiang Wang |author4=Zhijun Zhang |author5=Yongming Song |author6=Weihong Wang |author7=Qingwen Wang |title=The influence of zinc compounds on thermal stability and flame retardancy of wood flour polyvinyl chloride composites |journal=Construction and Building Materials |date=2022 |volume=320 |page=126203 |doi=10.1016/j.conbuildmat.2021.126203 |language=en}}</ref><ref>{{cite journal |author1=Junji Nemoto |author2=Keiichi Nakamata |title=All-cellulose material prepared using aqueous zinc chloride solution |journal=Cellulose |date=2022 |volume=29 |pages=2795–2803 |doi=10.1007/s10570-021-04344-1 |language=en}}</ref> Zinc chloride is also used as a deodorizing agent and to make ].<ref name="a" />
			==Safety and health==
			Zinc and chloride are essential for life. Zn<sup>2+</sup> is a component of several ]s, e.g., ] and ]. Thus, aqueous solutions of zinc chlorides are rarely problematic as an acute poison.<ref name="a"/> Anhydrous zinc chloride is however an aggressive ] as it can burn skin and other tissues. Ingestion of zinc chloride, often from ], requires endoscopic monitoring.<ref>{{cite journal |doi=10.1056/nejmra1810769 |title=Ingestion of Caustic Substances |date=2020 |last1=Hoffman |first1=Robert S. |last2=Burns |first2=Michele M. |last3=Gosselin |first3=Sophie |journal=New England Journal of Medicine |volume=382 |issue=18 |pages=1739–1748 |pmid=32348645 }}</ref> Another source of zinc chloride is ] ("HC") used in ]. Containing zinc oxide, ], and ] powder, release zinc chloride, carbon and ] smoke, an effective ].<ref>{{cite book | author = Sample, B. E. | year = 1997 | title = Methods for Field Studies of Effects of Military Smokes, Obscurants, and Riot-control Agents on Threatened and Endangered Species | publisher = DIANE Publishing | isbn = 978-1-4289-1233-5 }}</ref> Such smoke screens can lead to fatalities.<ref>{{cite book |doi=10.1016/C2011-0-07884-5 |title=Handbook on the Toxicology of Metals |date=2015 |isbn=978-0-444-59453-2|publisher = Academic Press|editor=Gunnar F. Nordberg, Bruce A. Fowler, Monica Nordberg}}</ref>
			==References==
			{{Reflist|colwidth=30em}}
			==Further reading==
			* N. N. Greenwood, A. Earnshaw, ''Chemistry of the Elements'', 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
			* {{RubberBible86th}}
			* ''The Merck Index'', 7th edition, Merck & Co, Rahway, New Jersey, USA, 1960.
			* D. Nicholls, ''Complexes and First-Row Transition Elements'', Macmillan Press, London, 1973.
			* J. March, ''Advanced Organic Chemistry'', 4th ed., p.&nbsp;723, Wiley, New York, 1992.
			* G. J. McGarvey, in ''Handbook of Reagents for Organic Synthesis, Volume 1: Reagents, Auxiliaries and Catalysts for C-C Bond Formation'', (R. M. Coates, S. E. Denmark, eds.), pp.&nbsp;220–3, Wiley, New York, 1999.
			==External links==
			*
			* .
			{{Zinc compounds}}
			{{Chlorides}}
			{{Authority control}}
			{{DEFAULTSORT:Zinc Chloride}}
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