Tungsten hexachloride

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Tungsten hexachloride
Tungsten hexachloride Hexachlorotungsten.svg
Tungsten hexachloride
3D view Tungsten-hexachloride-from-xtal-3D-balls.png
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Names
IUPAC names
Tungsten hexachloride
Tungsten(VI) chloride
Identifiers
3D model (JSmol)
ECHA InfoCard 100.032.980
EC Number
  • 236-293-9
PubChem CID
RTECS number
  • YO7710000
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
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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Infobox references

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 ReCl6 and MoCl6. The highly volatile WF6 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: Br, NCS, and RO (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

Epoxide class of chemical compounds

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.

Titanium tetrachloride 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 spectacular opaque clouds of titanium dioxide (TiO2) and hydrated hydrogen chloride. It is sometimes referred to as "tickle" or "tickle 4" due to the phonetic resemblance of its molecular formula (TiCl4) to the word.

Dysprosium(III) chloride chemical compound

Dysprosium(III) chloride (DyCl3), also known as dysprosium trichloride, is a compound of dysprosium and chlorine. It is a white to yellow solid which rapidly absorbs water on exposure to moist air to form a hexahydrate, DyCl3.6H2O. Simple rapid heating of the hydrate causes partial hydrolysis to an oxychloride, DyOCl.

Iron(II) chloride chemical compound

Iron(II) chloride, also known as ferrous chloride, is the chemical compound of formula FeCl2. It is a paramagnetic solid with a high melting point. The compound is white, but typical samples are often off-white. FeCl2 crystallizes from water as the greenish tetrahydrate, which is the form that is most commonly encountered in commerce and the laboratory. There is also a dihydrate. The compound is highly soluble in water, giving pale green solutions.

Tantalum(V) chloride 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.

Hafnium tetrachloride 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.

Boron trichloride is the inorganic compound with the formula BCl3. This colorless gas is a reagent in organic synthesis. It is highly reactive toward water.

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

Molybdenum(V) chloride chemical compound

Molybdenum(V) chloride is the inorganic compound with the formula [MoCl5]2. This dark volatile solid is used in research to prepare other molybdenum compounds. It is moisture-sensitive and soluble in chlorinated solvents. Usually called molybdenum pentachloride, it is in fact a dimer with the formula Mo2Cl10.

Trimethylsilyl cyanide chemical compound

Trimethylsilyl cyanide is the chemical compound with the formula (CH3)3SiCN. This volatile liquid consists of a cyanide group, that is CN, attached to a trimethylsilyl group. The molecule is used in organic synthesis as the equivalent of hydrogen cyanide. It is prepared by the reaction of lithium cyanide and trimethylsilyl chloride:

Tungsten(V) chloride 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.

Tungsten dichloride dioxide chemical compound

Tungsten dichloride dioxide 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.

Tungsten hexacarbonyl chemical compound

Tungsten hexacarbonyl (also called tungsten carbonyl) is the chemical compound with the formula W(CO)6. This complex gave rise to the first example of a dihydrogen complex.

Deoxygenation is a chemical reaction involving the removal of oxygen atoms from a molecule. The term also refers to the removal molecular oxygen (O2) from gases and solvents, a step in air-free technique and gas purifiers. As applied to organic compounds, deoxygenation is a component of fuels production as well a type of reaction employed in organic synthesis, e.g. of pharmaceuticals.

Rhenium pentachloride chemical compound

Rhenium pentachloride is an inorganic compound of chlorine and rhenium. The compound has the formula Re2Cl10 but it is usually referred to as rhenium pentachloride. It is a red-brown solid.

Molybdenum tetrachloride is the inorganic compound with the empirical formula MoCl4. The material exists as two polymorphs, a polymeric ("α") and a hexameric ("β") structures, although neither form is soluble in any solvent without degradation. In each polymorph, the Mo center is octahedral with two terminal chloride ligands and four doubly bridging ligands.

Oxophilicity is the tendency of certain chemical compounds to form oxides by hydrolysis or abstraction of oxygen, often from organic compounds. The term is often used to describe metal centers, commonly the early transition metals such as titanium, niobium, and tungsten. Oxophilic metals are classified as "hard" within the HSAB concept. Many main group compounds are also oxophilic, such as derivatives of aluminium, silicon, and phosphorus(V). The handling of oxophilic compounds often requires air-free techniques.

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.

Tungsten(II) chloride 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.

Tungsten(III) chloride 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.

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.CS1 maint: uses authors parameter (link).
  3. 1 2 M. H. Lietzke; M. L. Holt (1950). Tungsten(VI) Chloride (Tungsten Hexachloride). Inorganic Syntheses. 3. p. 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, 7, p. 121