Tungsten hexachloride
Encyclopedia
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. WCl6 is a rare example of a charge-neutral hexachloride, another example being ReCl6. Better known than WCl6 is the still more volatile WF6.
As a d0 ion, W(VI) forms diamagnetic derivatives. The hexachloride is octahedral
with equivalent W-Cl distances of 2.24 - 2.26 Å. In acceptor, the chloride ligand
s are donors in both sigma- and pi sense. Methylation with trimethylaluminium
affords hexamethyl tungsten
. Treatment with butyl lithium
affords a reagent that is useful for deoxygenation of epoxide
s.
The chloride ligands in WCl6 can be replaced by many anionic ligands including: Br−
, NCS−
, and RO−
(R = alkyl, aryl).
.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
of tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...
and chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
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. WCl6 is a rare example of a charge-neutral hexachloride, another example being ReCl6. Better known than WCl6 is the still more volatile WF6.
As a d0 ion, W(VI) forms diamagnetic derivatives. The hexachloride is octahedral
Octahedral molecular geometry
In chemistry, octahedral molecular geometry describes the shape of compounds where in six atoms or groups of atoms or ligands are symmetrically arranged around a central atom, defining the vertices of an octahedron...
with equivalent W-Cl distances of 2.24 - 2.26 Å. In acceptor, the chloride ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...
s are donors in both sigma- and pi sense. Methylation with trimethylaluminium
Trimethylaluminium
Trimethylaluminium is the chemical compound with the formula Al26, abbreviated as Al2Me6, 2 or the abbreviation TMA. This pyrophoric, colorless liquid is an industrially important organoaluminium compound...
affords hexamethyl tungsten
Hexamethyl tungsten
Hexamethyltungsten is the chemical compound W6. Classified as an organometallic compound, hexamethyltungsten is an air-sensitive, red, crystalline solid at room temperature; however, it is extremely volatile and sublimes at −30 °C...
. Treatment with butyl lithium
Butyl lithium
Butyllithium may refer to one of three isomeric organolithium reagents used in chemical synthesis:*n-Butyllithium, abbreviated BuLi or nBuLi*sec-Butyllithium, abbreviated sec-BuLi or sBuLi...
affords a reagent that is useful for deoxygenation of epoxide
Epoxide
An epoxide is a cyclic ether with three ring atoms. This ring approximately defines an equilateral triangle, which makes it highly strained. The strained ring makes epoxides more reactive than other ethers. Simple epoxides are named from the parent compound ethylene oxide or oxirane, such as in...
s.
The chloride ligands in WCl6 can be replaced by many anionic ligands including: Br−
Bromide
A bromide is a chemical compound containing bromide ion, that is bromine atom with effective charge of −1. The class name can include ionic compounds such as caesium bromide or covalent compounds such as sulfur dibromide.-Natural occurrence:...
, NCS−
Thiocyanate
Thiocyanate is the anion [SCN]−. It is the conjugate base of thiocyanic acid. Common derivatives include the colourless salts potassium thiocyanate and sodium thiocyanate. Organic compounds containing the functional group SCN are also called thiocyanates...
, and RO−
Alkoxide
An alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They can be written as RO−, where R is the organic substituent. Alkoxides are strong bases and, when R is not bulky, good nucleophiles and good ligands...
(R = alkyl, aryl).
Safety considerations
WCl6 is an aggressively corrosive oxidant, and hydrolyzes to release hydrogen chlorideHydrogen chloride
The compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
.