Zirconium(IV) chloride 4223925 215536869 2008-05-28T17:15:13Z DOI bot 6652755 Citation maintenance. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. {{Chembox new | ImageFile = Zirconium-tetrachloride-3D-balls-A.png | ImageSize = | Name = Zirconium(IV) chloride | OtherNames = Zirconium tetrachloride | Section1 = {{Chembox Identifiers | CASNo = 10026-11-6 | EINECS = 233-058-2 }} | Section2 = {{Chembox Properties | Formula = ZrCl<sub>4</sub> | MolarMass = 233.04 g/mol | Solvent = other solvents | SolubleOther = hydrolysis in [[water]]<br /> soluble in [[alcohol]] | MeltingPt = | BoilingPt = 331°C ''subl.''}} | Section4 = {{Chembox Thermochemistry | DeltaHf = -980.52 kJ/mol | Entropy = 181.41 J.K<sup>&ndash;1</sup>.mol<sup>&ndash;1</sup> | Cp = 125.38 J.K<sup>&ndash;1</sup>.mol<sup>&ndash;1</sup>}} }} '''Zirconium(IV) chloride''', also known as '''zirconium tetrachloride''', is the [[inorganic compound]] with the [[chemical formula|formula]] ZrCl<sub>4</sub>. This white high-melting solid hydrolyzes rapidly in humid air. It is a key [[reagent]] in the chemistry of [[zirconium]]. ==Structure== Unlike [[titanium(IV) chloride|TiCl<sub>4</sub>]], ZrCl<sub>4</sub> adopts a polymeric structure wherein each Zr is octahedrally coordinated. This difference in structures, polymeric vs. molecular, is responsible for the striking difference in their properties - one being distillable, the other being a high melting solid. In the solid state, ZrCl<sub>4</sub> adopts a tape-like linear polymeric structure--the same structure adopted by [[Hafnium(IV) chloride|HfCl<sub>4</sub>]]. This polymer degrades readily upon treatment with [[Lewis base]]s, which cleave the Zr-Cl-Zr linkages.<ref>N. N. Greenwood & A. Earnshaw, ''Chemistry of the Elements'' (2nd ed.), Butterworth-Heinemann, Oxford, '''1997'''.</ref> ==Kroll process== ZrCl<sub>4</sub> is an intermediate in the conversion of zirconium minerals to metallic [[zirconium]] by the [[Kroll process]]. In nature, zirconium minerals invaribly exists as oxides (reflected also by the tendency of all zirconium chlorides to hydrolyze). For their conversion to bulk metal, these refractory oxides are first converted to the tetrachloride, which can be distilled at high temperatures. This conversion entails treatment of the oxide with carbon as the oxide "getter" and chlorine. :ZrO<sub>2</sub> + 2 C + 2 Cl<sub>2</sub> → ZrCl<sub>4</sub> + 2 CO ==Chemical reactions== ZrCl<sub>4</sub> is the principal starting compound for the synthesis of many organometallic complexes of zironcium.<ref>New Aspects of Zirconium Containing Organic Compounds. Topics in Organometallic Chemistry, 10 Edited by Ilan Marek (Technion-Israel Institute of Technology, Haifa). Springer: Berlin, Heidelberg, New York. 2005. x + 176 pp. ISBN 3-540-22221-9.</ref> Because of its polymeric structure, ZrCl<sub>4</sub> it is usually converted to a molecular complex before use. It forms a 1:2 complex with [[tetrahydrofuran]]: CAS [21959-01-3], mp 175-177 °C.<ref>{{cite journal | author = L. E. Manxzer, Joe Deaton, Paul Sharp, R. R. Schrock | title = Tetrahydrofuran Complexes of Selected Early Transition Metals | journal = [[Inorganic Syntheses]] | year = 1982 | volume = 21 | pages = 135–40 | doi = 10.1002/9780470132524.ch31}}</ref> NaC<sub>5</sub>H<sub>5</sub> reacts with ZrCl<sub>4</sub>(THF)<sub>2</sub> to give zirconocene dichloride, ZrCl<sub>2</sub>(C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>, a versatile organozirconium complex.<ref>{{cite journal | author = [[Geoffrey Wilkinson|G. Wilkinson]] and J.G. Birmingham | year = 1954 | title = Bis-cyclopentadienyl Compounds of Ti, Zr, V, Nb and Ta | journal = [[J. Am. Chem. Soc.]] | volume = 76 | issue = 17 | pages = 4281–4284 | doi = 10.1021/ja01646a008}}</ref> One of the most curious properties of ZrCl<sub>4</sub> is its high solubility in the presence of methylated benzenes, such as [[durene]]. This solubilization arises through the formation of π-complexes.<ref>{{cite journal | author = Musso, F.; Solari, E.; Floriani, C.; Schenk, K. | title = Hydrocarbon Activation with Metal Halides: Zirconium Tetrachloride Catalyzing the Jacobsen Reaction and Assisting the Trimerization of Alkynes via the Formation of η<sup>6</sup>-Arene-Zirconium(IV) Complexes | journal = [[Organometallics]] | year = 1997 | volume = 16 | pages = 4889–4895 | doi = 10.1021/om970438g}}</ref> ==Uses== In organic synthesis zirconium tetrachloride is used as a weak [[Lewis acid]] for the [[Friedel-Crafts reaction]], the [[Diels-Alder reaction]] and intramolecular cyclisation reactions.<ref>{{cite journal | author= Bora U. | title= Zirconium Tetrachloride | journal= [[Synlett]] | year= 2003 | pages= 1073–1074 |doi=10.1055/s-2003-39323}}</ref> It is also used to make water-repellent [[textile]]s. {{commonscat|zirconium(IV) chloride}} ==References== {{Citationstyle|date=September 2007}} <references/> [[Category:Zirconium compounds]] [[Category:Chlorides]] [[Category:Metal halides]] [[Category:Coordination compounds]] [[de:Zirconium(IV)-chlorid]]