Vanadium(III) Chloride on:
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Vanadium trichloride is the inorganic compound with the formula VCl3. This purple salt is a common precursor to other vanadium(III) complexes.
With
Structure
VCl3 has the common BiI3 structure, a motif that features hexagonally closest-packed chloride framework with vanadium ions occupying the octahedral holes. VBr3 and VI3 adopt the same structure, but VF3 features a structure more closely related to ReO3. VCl3 isparamagnetic
Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, ...
and has two unpaired electrons.
Preparation and reactions
VCl3 is prepared by heating VCl4 at 160–170 °C under a flowing stream of inert gas, which sweeps out the Cl2. The bright red liquid converts to a purple solid. Heating of VCl3 decomposes with volatilization of VCl4, leaving VCl2. Upon heating under H2 at 675 °C (but less than 700 °C), VCl3 reduces to greenish VCl2. :: 2 VCl3 + H2 → 2 VCl2 + 2 HClComproportionation
Comproportionation or synproportionation is a chemical reaction where two reactants containing the same element but with different oxidation numbers, form a compound having an intermediate oxidation number. It is the opposite of disproportionation. ...
of vanadium trichloride and vanadium(V) oxides gives vanadium oxydichloride
Vanadium oxydichloride is the inorganic compound with the formula VOCl2. One of several oxychlorides of vanadium, it is a hygroscopic green solid. It is prepared by comproportionation of vanadium trichloride and vanadium(V) oxides:
:V2O5 + VO ...
:
:V2O5 + VOCl3 + 3 VCl3 → 6 VOCl2
Vanadium trichloride catalyses the pinacol coupling reaction A pinacol coupling reaction is an organic reaction in which a carbon–carbon bond is formed between the carbonyl groups of an aldehyde or a ketone in presence of an electron donor in a free radical process. The reaction product is a vicinal diol. ...
of benzaldehyde (PhCHO) to 1,2-diphenyl-1,2-ethanediol by various reducing metals such as zinc:
:Zn + 2 H2O + 2 PhCHO → (PhCH(OH))2 + Zn(OH)2
Complexes
VCl3 forms colorful adducts and derivatives with a broad scale of ligands. VCl3 dissolves in water to give thehexahydrate
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was underst ...
, but the formula is deceptive. The salt is described by the formula Cl2(H2O)4l.2H2O. In other words, two of the water molecules are not bound to the vanadium, whose structure resembles the corresponding Fe(III) derivative. Removal of the two bound chloride ligands from Cl2(H2O)4sup>+ in aqueous solution gives the green ion (H2O)6sup>3+.
With tetrahydrofuran
Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water- miscible organic liquid with low viscosity. It is ...
, VCl3 forms the red/pink complex VCl3(THF)3. Vanadium(III) chloride reacts with acetonitrile to give the green adduct VCl3(MeCN)3. When treated with KCN, VCl3 converts to (CN)7sup>4− (early metals commonly adopt coordination numbers greater than 6 with compact ligands). Complementarily, larger metals can form complexes with rather bulky ligands. This aspect is illustrated by the isolation of VCl3(NMe3)2, containing two bulky NMe3 ligands.
Organometallic derivatives
Vanadium(III) chloride as its thf complex is a precursor toV(mesityl
Mesitylene or 1,3,5-trimethylbenzene is a derivative of benzene with three methyl substituents positioned symmetrically around the ring. The other two isomeric trimethylbenzenes are 1,2,4-trimethylbenzene (pseudocumene) and 1,2,3-trimethylbenzene ...
)3.
:: VCl3(THF)3 + 3 LiC6H2-2,4,6-Me3 → V(C6H2-2,4,6-Me3)3(THF) + 3 LiCl
References
{{DEFAULTSORT:Vanadium(Iii) Chloride Vanadium(III) compounds Chlorides Metal halides