Tungsten hexachloride

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Tungsten hexachloride
Tungsten(VI) Chloride.jpg
α-Tungsten hexachloride
B-tungsten hexachloride.png
β-Tungsten hexachloride
Tungsten hexachloride Hexachlorotungsten.svg
Tungsten hexachloride
3D view Tungsten-hexachloride-from-xtal-3D-balls.png
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 396.54 g·mol−1
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
Related compounds
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 an inorganic chemical compound of tungsten and chlorine with the chemical formula W Cl 6. This dark violet-blue compound exists as volatile crystals 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 atom, tungsten hexachloride is diamagnetic.

Preparation and structure

Tungsten hexachloride can be prepared by chlorinating tungsten metal in a sealed tube at 600 °C: [2]

W + 3 Cl2 → WCl6

Tungsten hexachloride exists in both blue and red polymorphs, referred to respectively as α and β. The wine-red β can be obtained by rapid cooling, whereas the blue α form is more stable at room temperature. Although these polymorphs are distinctly colored, their molecular structures are very similar. Both polymorphs feature W Cl 6 molecules that have octahedral geometry, in which all six W–Cl bonds are equivalent, and their length is equal to 224–226 pm. The densities are very similar: 3.68 g/cm3 for α and 3.62 g/cm3 for β. The low-temperature form is slightly more dense, as expected. [3]

Reactions

Tungsten hexachloride 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. [2]

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, alkoxide, alkyl and aryl).

Reduction of WCl6 can be effected with a mixture of tetrachloroethylene and tetraphenylarsonium chloride: [5]

2 WCl6 + Cl2C=CCl2 + 2 (C6H5)4AsCl → 2 (C6H5)4As[WCl6] + Cl3C−CCl3

The W(V) hexachloride is a derivative of tungsten(V) chloride.

It reacts with arsenic or hydrogen arsenide to form tungsten arsenide. [6] [7]

Safety considerations

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

Related Research Articles

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

Tungsten(VI) fluoride, also known as tungsten hexafluoride, is an inorganic compound with the formula WF6. It is a toxic, corrosive, colorless gas, with a density of about 13 kg/m3 (22 lb/cu yd). It is the only known gaseous transition metal compound and the densest known gas under standard ambient temperature and pressure. WF6 is commonly used by the semiconductor industry to form tungsten films, through the process of chemical vapor deposition. This layer is used in a low-resistivity metallic "interconnect". It is one of seventeen known binary hexafluorides.

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

Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to PPh3 or Ph3P. It is versatile compound that is widely used as a reagent in organic synthesis and as a ligand for transition metal complexes, including ones that serve as catalysts in organometallic chemistry. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether.

<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">Platinum(II) chloride</span> Chemical compound

Platinum(II) chloride is the chemical compound PtCl2. It is an important precursor used in the preparation of other platinum compounds. It exists in two crystalline forms, but the main properties are somewhat similar: dark brown, insoluble in water, diamagnetic, and odorless.

<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">Triphenylarsine</span> Chemical compound

Triphenylarsine is the chemical compound with the formula As(C6H5)3. This organoarsenic compound, often abbreviated AsPh3, is a colorless crystalline solid that is used as a ligand and a reagent in coordination chemistry and organic synthesis. The molecule is pyramidal with As-C distances of 1.942–1.956 Å and C-As-C angles of 99.6–100.5°.

<span class="mw-page-title-main">Thiophosphoryl chloride</span> Chemical compound

Thiophosphoryl chloride is an inorganic compound with the chemical formula PSCl3. It is a colorless pungent smelling liquid that fumes in air. It is synthesized from phosphorus chloride and used to thiophosphorylate organic compounds, such as to produce insecticides.

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

Molybdenum tetrachloride is the inorganic compound with the empirical formula MoCl4. The material exists as two polymorphs, both being dark-colored paramagnetic solids. These compounds are mainly of interest as precursors to other molybdenum complexes.

Oxophilicity is the tendency of certain chemical compounds to form oxides by hydrolysis or abstraction of an oxygen atom from another molecule, often from organic compounds. The term is often used to describe metal centers, commonly the early transition metals such as titanium, niobium, and tungsten. Oxophilicity is often stated to be related to the hardness of the element, within the HSAB theory, but it has been shown that oxophilicity depends more on the electronegativity and effective nuclear charge of the element than on its hardness. This explains why the early transition metals, whose electronegativities and effective nuclear charges are low, are very oxophilic. Many main group compounds are also oxophilic, such as derivatives of aluminium, silicon, and phosphorus(III). The handling of oxophilic compounds often requires air-free techniques.

<span class="mw-page-title-main">Organomolybdenum chemistry</span> Chemistry of compounds with Mo-C bonds

Organomolybdenum chemistry is the chemistry of chemical compounds with Mo-C bonds. The heavier group 6 elements molybdenum and tungsten form organometallic compounds similar to those in organochromium chemistry but higher oxidation states tend to be more common.

Tungsten(IV) chloride is an inorganic compound with the formula WCl4. It is a diamagnetic black solid. The compound is of interest in research as one of a handful of binary tungsten chlorides.

<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.

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

In chemistry, a transition metal chloride complex is a coordination complex that consists of a transition metal coordinated to one or more chloride ligand. The class of complexes is extensive.

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


Methyldiphenylphosphine is the organophosphine with the formula CH3(C6H5)2P, often abbreviated PMePh2. It is a colorless, viscous liquid. It is a member of series (CH3)3-n(C6H5)2P that also includes n = 0, n = 1, and n = 3 that are often employed as ligands in metal phosphine complexes.

In chemistry, salt-free reduction describes methodology for reduction of metal halides by electron-rich trimethylsilyl reagents. Traditional reductions of metal halides are accomplished with alkali metals, a process that cogenerates alkali metal salts. Using the salt-free reduction, the reduction of metal halides is accompanied by formation of neutral organic compounds that can be easily removed from the inorganic or organometallic product. In addition to the reduction of metal halides, the reagents associated with this methodology are applicable to deoxygenation of organic substrates.

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

In chemistry, a transition metal ether complex is a coordination complex consisting of a transition metal bonded to one or more ether ligand. The inventory of complexes is extensive. Common ether ligands are diethyl ether and tetrahydrofuran. Common chelating ether ligands include the glymes, dimethoxyethane (dme) and diglyme, and the crown ethers. Being lipophilic, metal-ether complexes often exhibit solubility in organic solvents, a property of interest in synthetic chemistry. In contrast, the di-ether 1,4-dioxane is generally a bridging ligand.

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

Tungsten hexabromide, also known as tungsten(VI) bromide, is a chemical compound of tungsten and bromine with the formula WBr6. It is an air-sensitive dark grey powder that decomposes above 200 °C to tungsten(V) bromide and bromine.

<span class="mw-page-title-main">Transition metal complexes of phosphine oxides</span>

Transition metal complexes of phosphine oxides are coordination complex containing one or more phosphine oxide ligands. Many phosphine oxides exist and most behave as hard Lewis bases. Almost invariably, phosphine oxides bind metals by formation of M-O bonds.

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   978-0-471-93623-7..
  2. 1 2 M. H. Lietzke; M. L. Holt (1950). "Tungsten(VI) Chloride (Tungsten Hexachloride)". Inorganic Syntheses. Vol. 3. p. 163. doi:10.1002/9780470132340.ch44. ISBN   978-0-470-13162-6.
  3. 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. Bibcode:1974AcCrB..30.1216T. doi: 10.1107/S0567740874004572 ..
  4. M. A. Umbreit, K. B. Sharpless (1990). "Deoxygenation of Epoxides with Lower Valent Tungsten Halides: trans-Cyclododecene". Organic Syntheses ; Collected Volumes, vol. 7, p. 121.
  5. Uhl, G.; Hey, E.; Becker, G.; Weller, F.; Dehnicke, K. (1983). "Über die Reaktion von 2,2-Dimethylpropylidinphosphan mit Wolframhexachlorid; die Kristallstrukturen von [(Cl3PO)WCL4(H9C4CCC4H9)] und [(H5C6)4As][WCL6]". Zeitschrift für Anorganische und Allgemeine Chemie. 497 (2): 213–223. doi:10.1002/zaac.19834970221.
  6. Lassner, Erik; Schubert, Wolf-Dieter (2012-12-06). Tungsten. Springer Science & Business Media. p. 145. ISBN   978-1-4615-4907-9.
  7. Meyer, R. J. (2013-09-03). Wolfram (in German). Springer-Verlag. p. 207. ISBN   978-3-662-13401-6.