Zirconium(IV) chloride

Last updated
Zirconium(IV) chloride
Zirconium-tetrachloride-3D-balls-A.png
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Zirconium(IV) chloride.jpg
Names
IUPAC names
Zirconium tetrachloride
Zirconium(IV) chloride
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.030.041 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 233-058-2
PubChem CID
UNII
  • InChI=1S/4ClH.Zr/h4*1H;/q;;;;+4/p-4 Yes check.svgY
    Key: DUNKXUFBGCUVQW-UHFFFAOYSA-J Yes check.svgY
  • InChI=1/4ClH.Zr/h4*1H;/q;;;;+4/p-4
    Key: DUNKXUFBGCUVQW-XBHQNQODAQ
  • Cl[Zr](Cl)(Cl)Cl
Properties
ZrCl4
Molar mass 233.04 g/mol
Appearancewhite 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 concentrated HCl (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
−980.52 kJ/mol
Hazards
GHS labelling: [1]
GHS-pictogram-acid.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg
Danger
H290, H302, H312, H314, H317, H332, H334
P234, P260, P261, 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)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
3
0
2
W
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
1488-1500 mg/kg (oral, rat)
655 mg/kg (mouse, oral) [2]
Safety data sheet (SDS) MSDS
Related compounds
Other anions
Zirconium(IV) fluoride
Zirconium(IV) bromide
Zirconium(IV) iodide
Other cations
Titanium tetrachloride
Hafnium tetrachloride
Related compounds
 Zirconium(II) chloride, Zirconium(III) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Zirconium(IV) chloride, also known as zirconium tetrachloride, ( Zr Cl 4) is an inorganic compound frequently used as a precursor to other compounds of zirconium. This white high-melting solid hydrolyzes rapidly in humid air.

Contents

Structure

Unlike molecular TiCl4, 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, but ZrCl
4 is a solid. In the solid state, ZrCl4 adopts a tape-like linear polymeric structure—the same structure adopted by HfCl4. This polymer degrades readily upon treatment with Lewis bases, which cleave the Zr-Cl-Zr linkages. [4]

Synthesis

This conversion entails treatment of zirconium oxide with carbon in the presence of chlorine at high temperature:

ZrO2 + 2 C + 2 Cl2 → ZrCl4 + 2 CO

A laboratory scale process uses carbon tetrachloride in place of carbon and chlorine: [5]

ZrO2 + 2 CCl4 → ZrCl4 + 2 COCl2

Applications

Precursor to zirconium metal

ZrCl4 is an intermediate in the conversion of zirconium minerals to metallic zirconium by the Kroll 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 be distilled at high temperatures. The purified ZrCl4 can be reduced with Zr metal to produce zirconium(III) chloride.

Other uses

ZrCl4 is the most common precursor for chemical vapor deposition of zirconium dioxide and zirconium diboride. [6]

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. [7] It is also used to make water-repellent treatment of textiles and other fibrous materials.

Properties and reactions

Hydrolysis of ZrCl4 gives the hydrated hydroxy chloride cluster called zirconyl chloride. This reaction is rapid and virtually irreversible, consistent with the high oxophilicity of zirconium(IV). For this reason, manipulations of ZrCl4 typically require air-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 with tetrahydrofuran: CAS [21959-01-3], mp 175–177 °C. [9] Sodium cyclopentadienide (NaC5H5) reacts with ZrCl4(THF)2 to give zirconocene 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 as durene. 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 in torrs and temperature in kelvins. 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]

Related Research Articles

<span class="mw-page-title-main">Zirconium</span> Chemical element with atomic number 40 (Zr)

Zirconium is a chemical element; it has symbol Zr and atomic number 40. First isolated in pure form in 1824, the name zirconium is derived from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian zargun. It is a lustrous, grey-white, strong transition metal that closely resembles hafnium and, to a lesser extent, titanium.

A Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, is a catalyst used in the synthesis of polymers of 1-alkenes (alpha-olefins). Two broad classes of Ziegler–Natta catalysts are employed, distinguished by their solubility:

<span class="mw-page-title-main">Titanium tetrachloride</span> Inorganic chemical compound

Titanium tetrachloride is the inorganic compound with the formula TiCl4. It is an important intermediate in the production of titanium metal and the pigment titanium dioxide. TiCl4 is a volatile liquid. Upon contact with humid air, it forms thick clouds of titanium dioxide and hydrochloric acid, a reaction that was formerly exploited for use in smoke machines. It is sometimes referred to as "tickle" or "tickle 4", as a phonetic representation of the symbols of its molecular formula.

<span class="mw-page-title-main">Hafnium tetrachloride</span> Chemical compound

Hafnium(IV) chloride is the inorganic compound with the formula HfCl4. This colourless solid is the precursor to most hafnium organometallic compounds. It has a variety of highly specialized applications, mainly in materials science and as a catalyst.

<span class="mw-page-title-main">Titanocene dichloride</span> Chemical compound

Titanocene dichloride is the organotitanium compound with the formula (η5-C5H5)2TiCl2, commonly abbreviated as Cp2TiCl2. This metallocene is a common reagent in organometallic and organic synthesis. It exists as a bright red solid that slowly hydrolyzes in air. It shows antitumour activity and was the first non-platinum complex to undergo clinical trials as a chemotherapy drug.

Zirconium(IV) bromide is the inorganic compound with the formula ZrBr4. This colourless solid is the principal precursor to other Zr–Br compounds.

<span class="mw-page-title-main">Schwartz's reagent</span> Chemical compound

Schwartz's reagent is the common name for the organozirconium compound with the formula (C5H5)2ZrHCl, sometimes called zirconocene hydrochloride or zirconocene chloride hydride, and is named after Jeffrey Schwartz, a chemistry professor at Princeton University. This metallocene is used in organic synthesis for various transformations of alkenes and alkynes.

<span class="mw-page-title-main">Organotitanium chemistry</span>

Organotitanium chemistry is the science of organotitanium compounds describing their physical properties, synthesis, and reactions. Organotitanium compounds in organometallic chemistry contain carbon-titanium chemical bonds. They are reagents in organic chemistry and are involved in major industrial processes.

Niobocene dichloride is the organometallic compound with the formula (C5H5)2NbCl2, abbreviated Cp2NbCl2. This paramagnetic brown solid is a starting reagent for the synthesis of other organoniobium compounds. The compound adopts a pseudotetrahedral structure with two cyclopentadienyl and two chloride substituents attached to the metal. A variety of similar compounds are known, including Cp2TiCl2.

<span class="mw-page-title-main">Organozirconium and organohafnium chemistry</span>

Organozirconium chemistry is the science of exploring the properties, structure, and reactivity of organozirconium compounds, which are organometallic compounds containing chemical bonds between carbon and zirconium. Organozirconium compounds have been widely studied, in part because they are useful catalysts in Ziegler-Natta polymerization.

Zirconocene dichloride is an organozirconium compound composed of a zirconium central atom, with two cyclopentadienyl and two chloro ligands. It is a colourless diamagnetic solid that is somewhat stable in air.

Organovanadium chemistry is the chemistry of organometallic compounds containing a carbon (C) to vanadium (V) chemical bond. Organovanadium compounds find only minor use as reagents in organic synthesis but are significant for polymer chemistry as catalysts.

<span class="mw-page-title-main">Zirconium(III) chloride</span> Chemical compound

Zirconium(III) chloride is an inorganic compound with formula ZrCl3. It is a blue-black solid that is highly sensitive to air.

In organometallic chemistry, bent metallocenes are a subset of metallocenes. In bent metallocenes, the ring systems coordinated to the metal are not parallel, but are tilted at an angle. A common example of a bent metallocene is Cp2TiCl2. Several reagents and much research is based on bent metallocenes.

<span class="mw-page-title-main">Titanium ethoxide</span> Chemical compound

Titanium ethoxide is a chemical compound with the formula Ti4(OCH2CH3)16. It is a commercially available colorless liquid that is soluble in organic solvents but hydrolyzes readily. Its structure is more complex than suggested by its empirical formula. Like other alkoxides of titanium(IV) and zirconium(IV), it finds used in organic synthesis and materials science.

<span class="mw-page-title-main">(Cyclopentadienyl)titanium trichloride</span> Chemical compound

(Cyclopentadienyl)titanium trichloride is an organotitanium compound with the formula (C5H5)TiCl3. It is a moisture sensitive orange solid. The compound adopts a piano stool geometry.

<span class="mw-page-title-main">Hafnocene dichloride</span> Chemical compound

Hafnocene dichloride is the organohafnium compound with the formula (C5H5)2HfCl2. It is a white solid that is sparingly soluble in some organic solvents. The lighter homologues zirconacene dichloride and titanocene dichloride have received much more attention. While hafnocene is only of academic interest, some more soluble derivatives are precatalysts for olefin polymerization. Moreso than the Zr analogue, this compound is highly resistant to reduction.

The +4 oxidation state dominates titanium chemistry, but compounds in the +3 oxidation state are also numerous. Commonly, titanium adopts an octahedral coordination geometry in its complexes, but tetrahedral TiCl4 is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree of covalent bonding.

Hafnium compounds are compounds containing the element hafnium (Hf). Due to the lanthanide contraction, the ionic radius of hafnium(IV) (0.78 ångström) is almost the same as that of zirconium(IV) (0.79 angstroms). Consequently, compounds of hafnium(IV) and zirconium(IV) have very similar chemical and physical properties. Hafnium and zirconium tend to occur together in nature and the similarity of their ionic radii makes their chemical separation rather difficult. Hafnium tends to form inorganic compounds in the oxidation state of +4. Halogens react with it to form hafnium tetrahalides. At higher temperatures, hafnium reacts with oxygen, nitrogen, carbon, boron, sulfur, and silicon. Some compounds of hafnium in lower oxidation states are known.

References

  1. ↑ GHS: PubChem
  2. ↑ "Zirconium compounds (as Zr)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. "New Environment Inc. - NFPA Chemicals". newenv.com. Retrieved 26 April 2017.
  4. ↑ N. N. Greenwood & A. Earnshaw, Chemistry of the Elements (2nd ed.), Butterworth-Heinemann, Oxford, 1997.
  5. ↑ Hummers, W. S.; Tyree, S. Y.; Yolles, S. (1953). "Zirconium and Hafnium Tetrachlorides". Inorganic Syntheses. Vol. IV. McGraw-Hill Book Company, Inc. p. 121. doi:10.1002/9780470132357.ch41. ISBN   978-0-470-13235-7.
  6. ↑ Randich, E. (1 November 1979). "Chemical vapor deposited borides of the form (Ti,Zr)B2 and (Ta,Ti)B2". Thin Solid Films. 63 (2): 309–313. Bibcode:1979TSF....63..309R. doi:10.1016/0040-6090(79)90034-8.
  7. ↑ Bora U. (2003). "Zirconium Tetrachloride". Synlett (7): 1073–1074. doi: 10.1055/s-2003-39323 .
  8. ↑ Ilan Marek, ed. (2005). New Aspects of Zirconium Containing Organic Compounds. Topics in Organometallic Chemistry. Vol. 10. Springer: Berlin, Heidelberg, New York. doi:10.1007/b80198. ISBN   978-3-540-22221-7. ISSN   1436-6002.
  9. ↑ L. E. Manzer; Joe Deaton (1982). "31. Tetragtdrfuran Complexes of Selected Early Transition Metals". Inorganic Syntheses. Vol. 21. pp. 135–140. doi:10.1002/9780470132524.ch31. ISBN   978-0-470-13252-4.
  10. ↑ Wilkinson, G.; Birmingham, J. G. (1954). "Bis-cyclopentadienyl Compounds of Ti, Zr, V, Nb and Ta". J. Am. Chem. Soc. 76 (17): 4281–4284. doi:10.1021/ja01646a008.
  11. ↑ Musso, F.; Solari, E.; Floriani, C.; Schenk, K. (1997). "Hydrocarbon Activation with Metal Halides: Zirconium Tetrachloride Catalyzing the Jacobsen Reaction and Assisting the Trimerization of Alkynes via the Formation of η6-Arene-Zirconium(IV) Complexes". Organometallics . 16 (22): 4889–4895. doi:10.1021/om970438g.
  12. ↑ Palko, A. A.; Ryon, A. D.; Kuhn, D. W. (March 1958). "The Vapor Pressures of Zirconium Tetrachloride and Hafnium Tetrachloride". J. Phys. Chem. 62 (3): 319–322. doi:10.1021/j150561a017. hdl: 2027/mdp.39015086513051 .

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