Chemistry:Vanadium tetrachloride

Short description: Chemical reagent used to produce other vanadium compounds

Vanadium tetrachloride

Structural formula of the vanadium tetrachloride molecule 3D model of the vanadium tetrachloride molecule
Names
IUPAC names Vanadium tetrachloride Vanadium(IV) chloride
Identifiers
CAS Number	7632-51-1 Y
3D model (JSmol)	Interactive image
ChemSpider	19956660 Y
EC Number	231-561-1
PubChem CID	24273
RTECS number	YW2625000
UNII	2I17MGM5YJ Y
InChI InChI=1S/4ClH.2V/h4*1H;;/q;;;;2*+2/p-4 Y Key: UNUHYFVFMNJHJW-UHFFFAOYSA-J Y InChI=1/4ClH.2V/h4*1H;;/q;;;;2*+2/p-4 Key: UNUHYFVFMNJHJW-XBHQNQODAR
SMILES Cl[V](Cl)(Cl)Cl
Properties
Chemical formula	VCl4
Molar mass	192.75 g/mol
Appearance	bright red liquid, moisture sensitive
Odor	pungent
Density	1.816 g/cm3, liquid
Melting point	−24.5 °C (−12.1 °F; 248.7 K)
Boiling point	148 °C (298 °F; 421 K)
Solubility in water	decomposes
Solubility	soluble in CH2Cl2
Vapor pressure	7.9 Pa
Magnetic susceptibility (χ)	+1130.0·10−6 cm3/mol
Structure
Coordination geometry	tetrahedral
Dipole moment	0 D
Hazards
Main hazards	toxic; oxidizer; hydrolyzes to release HCl
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	HH301Category:GHS errors, HH311Category:GHS errors, HH314Category:GHS errors, HH331Category:GHS errors
GHS precautionary statements	PP260Category:GHS errors, PP261Category:GHS errors, PP262Category:GHS errors, PP264Category:GHS errors, PP270Category:GHS errors, PP271Category:GHS errors, PP280Category:GHS errors, PP301+P316Category:GHS errors, PP301+P330+P331Category:GHS errors, PP302+P352Category:GHS errors, PP302+P361+P354Category:GHS errors, PP304+P340Category:GHS errors, PP305+P354+P338Category:GHS errors, PP316Category:GHS errors, PP321Category:GHS errors, PP330Category:GHS errors, PP361+P364Category:GHS errors, PP363Category:GHS errors, PP403+P233Category:GHS errors, PP405Category:GHS errors, PP501Category:GHS errors
NFPA 704 (fire diamond)	0 3 2 W
Lethal dose or concentration (LD, LC):
LD50 (median dose)	160 mg/kg (rat, oral)
Related compounds
Other anions	Vanadium tetrafluoride Vanadium disulfide Vanadium tetrabromide
Other cations	Titanium tetrachloride Chromium tetrachloride Niobium tetrachloride Tantalum tetrachloride
Related compounds	Vanadium trichloride
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

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.

Synthesis, bonding, basic properties

With one more valence electron than diamagnetic TiCl₄, VCl₄ is a paramagnetic liquid. It is one of only a few paramagnetic compounds that is liquid at room temperature.

VCl₄ is prepared by chlorination of vanadium metal. VCl₅ does not form in this reaction; Cl₂ lacks the oxidizing power to attack VCl₄. VCl₅ can however be prepared indirectly from VF₅ at −78 °C.

Reactions

Consistent with its high oxidizing power, VCl₄ reacts with HBr at -50 °C to produce VBr₃. The reaction proceeds via VBr₄, which releases Br₂ during warming to room temperature.

2 VCl₄ + 8 HBr → 2 VBr₃ + 8 HCl + Br₂

VCl₄ forms adducts with many donor ligands, for example, VCl₄(THF)₂.

It is the precursor to vanadocene dichloride.

Organic chemistry

In organic synthesis, VCl₄ is used for the oxidative coupling of phenols. For example, it converts phenol into a mixture of 4,4'-, 2,4'-, and 2,2'-biphenols:

2 C₆H₅OH + 2 VCl₄ → HOC₆H₄–C₆H₄OH + 2 VCl₃ + 2 HCl

Applications

VCl₄ is a catalyst for the polymerization of alkenes, especially those useful in the rubber industry. The underlying technology is related to Ziegler–Natta catalysis, which involves the intermediacy of vanadium alkyls.