| Vanadium tetrachloride | |
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Vanadium tetrachloride |
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| Identifiers | |
| CAS number | 7632-51-1 |
| PubChem | 24273 |
| ChemSpider | 19956660 |
| RTECS number | YW2625000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | VCl4 |
| Molar mass | 192.75 g/mol |
| Appearance | bright red liquid, moisture sensitive |
| Density | 1.816 g/cm3, liquid |
| Melting point |
−28 °C |
| Boiling point |
154 °C |
| Solubility in water | decomposes |
| Solubility in other solvents | chlorocarbons |
| Vapor pressure | 7.9 Pa |
| Structure | |
| Coordination geometry |
tetrahedral |
| Dipole moment | 0 D |
| Hazards | |
| EU Index | Not listed |
| Main hazards | oxidizer; hydrolyzes to release HCl |
| NFPA 704 |
0
3
2
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| Related compounds | |
| Other anions | vanadium tetrafluoride, vanadium disulfide, vanadium tetrabromide |
| Other cations | titanium tetrachloride, chromium tetrachloride, niobium tetrachloride, tantalum tetrachloride |
| Related compounds | vanadium trichloride |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Vanadium tetrachloride is the inorganic compound with the formula VCl4. This bright red liquid is a useful reagent for the preparation of other vanadium compounds.
Contents |
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; Cl2 lacks the oxidizing power to attack VCl4. In contrast, the heavier analogues NbCl5 and TaCl5 are stable and not particularly oxidizing. Of course, VF5 does exist, reflecting the increased oxidizing power of F2 vs Cl2. Indicative of its oxidizing power, VCl4 releases Cl2 at its boiling point (standard pressure) to afford vanadium(III) chloride.
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.[1]
VCl4 forms adducts with many donor ligands, for example, VCl4(THF)2.
It is the precursor to vanadocene dichloride.
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.
In organic synthesis, VCl4 is used to couple phenols. For example, it converts phenol into 4,4'-biphenol.[2] It is reduced to VCl3 in the process.
This reaction highlights the oxidizing ability of VCl4, consistent with it being resistant to further oxidation by Cl2.
VCl4 is a volatile, aggressive oxidant that readily hydrolyzes to release HCl.
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