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| Names | |
|---|---|
| IUPAC names Zirconium tetrachloride Zirconium(IV) chloride | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChemSpider |
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| ECHA InfoCard | 100.030.041 |
| EC Number |
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| UNII | |
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| Properties | |
| ZrCl4 | |
| Molar mass | 233.04 g/mol |
| Appearance | white crystals |
| Density | 2.80 g/cm3 |
| Melting point | 437 °C (819 °F; 710 K) (triple point) |
| Boiling point | 331 °C (628 °F; 604 K) (sublimes) |
| hydrolysis | |
| Solubility | concentratedHCl (with reaction) |
| Structure | |
| Monoclinic,mP10 | |
| P12/c1, No. 13 | |
| Thermochemistry | |
| 125.38 J K−1 mol−1 | |
Std molar entropy(S⦵298) | 181.41 J K−1 mol−1 |
Std enthalpy of formation(ΔfH⦵298) | −980.52 kJ/mol |
| Hazards | |
| GHS labelling:[2] | |
   | |
| Danger | |
| H290,H302,H312,H314,H317,H332,H334 | |
| P234,P260,P264,P270,P271,P272,P280,P285,P301+P312,P301+P330+P331,P302+P352,P303+P361+P353,P304+P312,P304+P340,P304+P341,P305+P351+P338,P310,P312,P321,P322,P330,P333+P313,P342+P311,P363,P390,P404,P405,P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 1488-1500 mg/kg (oral, rat) 655 mg/kg (mouse, oral)[1] |
| Safety data sheet (SDS) | MSDS |
| Related compounds | |
Otheranions | Zirconium(IV) fluoride Zirconium(IV) bromide Zirconium(IV) iodide |
Othercations | Titanium tetrachloride Hafnium tetrachloride |
Related compounds | Zirconium(II) chloride,Zirconium(III) chloride |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Zirconium(IV) chloride, also known aszirconium tetrachloride, (ZrCl4) is aninorganic compound frequently used as a precursor to other compounds of zirconium. This white high-melting solid hydrolyzes rapidly in humid air.
Unlike molecularTiCl4, solid ZrCl4 adopts a polymeric structure wherein each Zr is octahedrally coordinated. This difference in structures is responsible for the disparity in their properties:TiCl
4 is distillable, butZrCl
4 is a solid. In the solid state, ZrCl4 adopts a tape-like linear polymeric structure—the same structure adopted byHfCl4. This polymer degrades readily upon treatment withLewis bases, which cleave the Zr-Cl-Zr linkages.[4]
This conversion entails treatment of zirconium oxide with carbon in the presence of chlorine at high temperature:
A laboratory scale process usescarbon tetrachloride in place of carbon and chlorine:[5]
ZrCl4 is an intermediate in the conversion of zirconium minerals to metalliczirconium by theKroll process. In nature, zirconium minerals usually exist 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 bedistilled at high temperatures. The purified ZrCl4 can be reduced with Zr metal to producezirconium(III) chloride.
ZrCl4 is the most common precursor forchemical vapor deposition ofzirconium dioxide andzirconium diboride.[6]
In organic synthesis zirconium tetrachloride is used as a weakLewis acid for theFriedel-Crafts reaction, theDiels-Alder reaction and intramolecular cyclisation reactions.[7] It is also used to make water-repellent treatment oftextiles and other fibrous materials.
Hydrolysis of ZrCl4 gives the hydrated hydroxy chloride cluster calledzirconyl chloride. This reaction is rapid and virtually irreversible, consistent with the highoxophilicity of zirconium(IV). For this reason, manipulations of ZrCl4 typically requireair-free techniques.
ZrCl4 is the principal starting compound for the synthesis of many organometallic complexes of zirconium.[8] Because of its polymeric structure, ZrCl4 is usually converted to a molecular complex before use. It forms a 1:2 complex withtetrahydrofuran: CAS [21959-01-3], mp 175–177 °C.[9]Sodium cyclopentadienide (NaC5H5) reacts with ZrCl4(THF)2 to givezirconocene dichloride, ZrCl2(C5H5)2, a versatile organozirconium complex.[10] One of the most curious properties of ZrCl4 is its high solubility in the presence of methylated benzenes, such asdurene. This solubilization arises through the formation of π-complexes.[11]
The log (base 10) of the vapor pressure of zirconium tetrachloride (from 480 to 689 K) is given by the equation: log10(P) = −5400/T + 11.766, where the pressure is measured intorrs and temperature inkelvins. The log (base 10) of the vapor pressure of solid zirconium tetrachloride (from 710 to 741 K) is given by the equation log10(P) = −3427/T + 9.088. The pressure at the melting point is 14,500 torrs.[12]
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