Tungsten hexachloride

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Tungsten hexachloride
Tungsten(VI) Chloride.jpg
Tungsten hexachloride Hexachlorotungsten.svg
Tungsten hexachloride
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3D view
Names
IUPAC names
Tungsten hexachloride
Tungsten(VI) chloride
Identifiers
3D model (JSmol)
ECHA InfoCard 100.032.980 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 236-293-9
PubChem CID
RTECS number
  • YO7710000
UNII
  • InChI=1S/6ClH.W/h6*1H;/q;;;;;;+6/p-6
  • Cl[W](Cl)(Cl)(Cl)(Cl)Cl
Properties
WCl6
Molar mass 396.61 g/mol
Appearancedark blue crystals, moisture sensitive
Density 3.52 g/cm3
Melting point 275 °C (527 °F; 548 K)
Boiling point 346.7 °C (656.1 °F; 619.8 K)
hydrolyzes
Solubility in chlorocarbonssoluble
71.0·10−6 cm3/mol
Structure
α:rhombohedral, β: hexagonal
octahedral
0 D
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
oxidizer; hydrolysis releases HCl
Related compounds
Other anions
Tungsten hexafluoride
Tungsten hexabromide
Other cations
Molybdenum(V) chloride
Chromyl chloride
Related compounds
Tungsten(IV) chloride
Tungsten(V) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tungsten hexachloride is the chemical compound of tungsten and chlorine with the formula WCl6. This dark violet blue species exists as a volatile solid under standard conditions. It is an important starting reagent in the preparation of tungsten compounds. [1] Other examples of charge-neutral hexachlorides are rhenium(VI) chloride and molybdenum(VI) chloride. The highly volatile tungsten hexafluoride is also known.

Contents

As a d0 ion, W(VI) forms diamagnetic derivatives. The hexachloride is octahedral with equivalent W–Cl distances of 2.24–2.26 Å. [2]

Preparation

Tungsten hexachloride can be prepared by chlorinating tungsten metal in a sealed tube at 600 °C: [3]

W + 3 Cl2 → WCl6

Properties and Reactions

Tungsten (VI) chloride is a blue-black solid at room temperature. At lower temperatures, it becomes wine-red in color. A red form of the compound can be made by rapidly condensing its vapor, which reverts to the blue-black form on gentle heating. It is readily hydrolyzed, even by moist air, giving the orange oxychlorides WOCl4 and WO2Cl2, and subsequently, tungsten trioxide. WCl6 is soluble in carbon disulfide, carbon tetrachloride, and phosphorus oxychloride. [3]

Methylation with trimethylaluminium affords hexamethyl tungsten:

WCl6 +3 Al2(CH3)6 → W(CH3)6 + 3 Al2(CH3)4Cl2

Treatment with butyl lithium affords a reagent that is useful for deoxygenation of epoxides. [4]

The chloride ligands in WCl6 can be replaced by many anionic ligands including: bromide, thiocyanate and alkoxide (R = alkyl, aryl).

Reduction of WCl6 gives, sequentially, tungsten(V) chloride and tungsten(IV) chloride.

Safety considerations

WCl6 is an aggressively corrosive oxidant, and hydrolyzes to release hydrogen chloride.

Related Research Articles

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In organic chemistry, an epoxide is a cyclic ether with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale for many applications. In general, low molecular weight epoxides are colourless and nonpolar, and often volatile.

In organic chemistry, an acyl chloride is an organic compound with the functional group −C(=O)Cl. Their formula is usually written R−COCl, where R is a side chain. They are reactive derivatives of carboxylic acids. A specific example of an acyl chloride is acetyl chloride, CH3COCl. Acyl chlorides are the most important subset of acyl halides.

<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" due to the phonetic resemblance of its molecular formula to the word.

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

Tantalum(V) chloride, also known as tantalum pentachloride, is an inorganic compound with the formula TaCl5. It takes the form of a white powder and is commonly used as a starting material in tantalum chemistry. It readily hydrolyzes to form tantalum(V) oxychloride (TaOCl3) and eventually tantalum pentoxide (Ta2O5); this requires that it be synthesised and manipulated under anhydrous conditions, using air-free techniques.

<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.

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Vanadium tetrachloride is the inorganic compound with the formula VCl4. This reddish-brown liquid serves as a useful reagent for the preparation of other vanadium compounds.

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

Molybdenum(V) chloride is the inorganic compound with the empirical formula MoCl5. This dark volatile solid is used in research to prepare other molybdenum compounds. It is moisture-sensitive and soluble in chlorinated solvents.

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

Tungsten(V) chloride is an inorganic compound with the formula W2Cl10. This compound is analogous in many ways to the more familiar molybdenum pentachloride.

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

Tungsten dichloride dioxide, or Tungstyl chloride is the chemical compound with the formula WO2Cl2. It is a yellow-colored solid. It is used as a precursor to other tungsten compounds. Like other tungsten halides, WO2Cl2 is sensitive to moisture, undergoing hydrolysis.

<span class="mw-page-title-main">Tungsten hexacarbonyl</span> Chemical compound

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4
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<span class="mw-page-title-main">Tungsten(II) chloride</span> Chemical compound

Tungsten(II) chloride is the inorganic compound with the formula W6Cl12. It is a polymeric cluster compound. The material dissolves in concentrated hydrochloric acid, forming (H3O)2[W6Cl14](H2O)x. Heating this salt gives yellow-brown W6Cl12. The structural chemistry resembles that observed for molybdenum(II) chloride.

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

Tungsten(III) chloride is the inorganic compound with the formula W6Cl18. It is a cluster compound. It is a brown solid, obtainable by chlorination of tungsten(II) chloride. Featuring twelve doubly bridging chloride ligands, the cluster adopts a structure related to the corresponding chlorides of niobium and tantalum. In contrast, W6Cl12 features eight triply bridging chlorides.

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<span class="mw-page-title-main">Transition metal ether complex</span>

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References

  1. J. W. Herndon; M. E. Jung (2007). "Tungsten(VI) Chloride". Encyclopedia of Reagents for Organic Synthesis. Wiley. doi:10.1002/9780470842898.rt430.pub2. ISBN   978-0471936237..
  2. J. C. Taylor, P. W. Wilson (1974). "The Structure of β-Tungsten Hexachloride by Powder Neutron and X-ray Diffraction". Acta Crystallographica. B30 (5): 1216–1220. doi: 10.1107/S0567740874004572 .{{cite journal}}: CS1 maint: uses authors parameter (link).
  3. 1 2 M. H. Lietzke; M. L. Holt (1950). "Tungsten(VI) Chloride (Tungsten Hexachloride)". Inorganic Syntheses. 3: 163. doi:10.1002/9780470132340.ch4.
  4. M. A. Umbreit, K. B. Sharpless (1990). "Deoxygenation of Epoxides with Lower Valent Tungsten Halides: trans-Cyclododecene". Organic Syntheses .; Collective Volume, vol. 7, p. 121