Vanadium Compounds chloride

Some properties of selected vanadium compounds are Hsted in Table 1. Detailed solubiUty data are available (3), as are physical constants of other vanadium compounds (4). Included are the lattice energy of several metavanadates and the magnetic susceptibiUty of vanadium bromides, chlorides, fluorides, oxides, and sulfides (5). 

Vanadium, a typical transition element, displays weU-cliaractetized valence states of 2—5 in solid compounds and in solutions. Valence states of —1 and 0 may occur in solid compounds, eg, the carbonyl and certain complexes. In oxidation state 5, vanadium is diamagnetic and forms colorless, pale yeUow, or red compounds. In lower oxidation states, the presence of one or more 3d electrons, usually unpaired, results in paramagnetic and colored compounds. All compounds of vanadium having unpaired electrons are colored, but because the absorption spectra may be complex, a specific color does not necessarily correspond to a particular oxidation state. As an illustration, vanadium(IV) oxy salts are generally blue, whereas vanadium(IV) chloride is deep red. Differences over the valence range of 2—5 are shown in Table 2. The stmcture of vanadium compounds has been discussed (6,7). 

Vanadium (IV) Chloride. Vanadium(IV) chloride (vanadium tetrachloride, VCy is a red-brown hquid, is readily hydrolyzed, forms addition compounds with donor solvents such as pyridine, and is reduced by such molecules to trivalent vanadium compounds. Vanadium tetrachloride dissociates slowly at room temperature and rapidly at higher temperatures, yielding VCl and CI2. Decomposition also is induced catalyticahy and photochemically. This instabihty reflects the difficulty in storing and transporting it for industrial use. 

Vanadium(III) Chloride. Vanadium(III) chloride (vanadium trichloride, VCl ) is a pink-violet sohd, is readily hydrolyzed, and is insoluble in nonpolar solvents but dissolves in donor solvents, eg, acetonitrile, to form coordination compounds. Chemical behavior of the tribromide (VBr ) is similar to that of VCl. ... 

The liberated iodine and the excess of iodide is determined by titration with standard potassium iodate solution the hydrochloric acid concentration must not be allowed to fall below 7JVf in order to prevent re-oxidation of the vanadium compound by iodine chloride. 

Vanadium compounds in a low oxidation state are known to be effective for inducing one-electron reduction. The highly stereoselective monodebromination of gem-dibromocyclopropanes proceeds with the help of a low-valent vanadium species generated from vanadium(III) chloride and zinc in dimethoxyethane in cooperation with diethyl phosphonate or triethyl phosphite... 

The ability of vanadium(II) chloride to facilitate sulfoxide deoxygenation has been discussed (Section IV,C), and it appears that vana-dium(III) sulfoxide complexes may be prepared by air oxidation of van-adium(II) salts in the presence of the sulfoxide. In this manner, [V(Me2S0)6][C104]3 was prepared from vanadium(II) perchlorate (119) and the kinetics of substitution with thiocyanate ion detailed. Care is necessary in handling the pure compound, as it is reported to be sensitive to detonation. A large number of oxovanadium(IV) species have... 

Trivalent Compounds.—In trivalent vanadium compounds the basic character of the element is well developed, and both normal and oxy-salts of the sesquioxide V203 are well defined, e.g. vanadous sulphate, V2(S04)3, and vanadium oxymonochloride, VOC1. It has been previously mentioned that resemblances between the elements of the A and B Subdivisions of Group V. are mainly restricted to the pentavalent compounds it is of interest to note that the oxychloride has analogues in the trivalent antimony and bismuth basic chlorides, SbOCl and BiOCl. Trivalent vanadium also displays considerable analogy, however, with other trivalent transitional elements, as shown by the following —... 

Vanadyl salts are salts of tetravalent vanadium, and contain the divalent [VO]- radical. Many vanadium compounds are known which appear to contain a [VO] group, but the vanadium is either trivalent or pentavalent. Throughout this book the term vanadyl is restricted to compounds of tetravalent vanadium, that is, to salts of the oxide V02. Hence, for example, the compound VOCI3, which contains pentavalent vanadium, is called vanadium oxytrichloride, and not by the more usual but less logical name vanadyl chloride. ... 

Sodium tungstate, 145 Tungsten carbonyl, 49 Vanadium Compounds Alkynylvanadium(III) chloride,... 

Organovanadium reagents, 219 Phenylmagnesium bromide-Vanadi-um(III) chloride, 219 Vanadium(III) chloride, 219 Vanadyl acetylacetonate, 54 Vanadyl trichloride, 289 Zinc Compounds Bis(acetylacetonate)zinc(II), 33... 

Although low-temperature syndiospecific polymerisation of propylene with soluble Ziegler-Natta catalysts, based on soluble vanadium compounds and dialkylaluminium chlorides as activators, was first carried out successfully as... 

VANADIUM BROMIDE see VEKOOO VANADIUM CHLORIDE see VEFOOO VANADIUM(III) CHLORIDE see VEPOOO VANADIUM COMPOUNDS see VCZOOO VANADIUM DUST and FUME (ACGIH) see VDUOOO VANADIUM DUST and FUME (ACGIH) see VDZOOO VANADIUM (OSHA) see VDZOOO VANADIUM OXIDE see VEAOOO VANADIUM(V) OXIDE see VDUOOO VANADIUM OXYTRICHLORIDE see VDPOOO VANADIUM PENTAOXIDE see VDUOOO VANADIUMPENTOXID (GERMAN) see VDUOOO VANADIUM PENTOXIDE (dust) see VDUOOO VANADIUM PENTOXIDE (fume) see VDZOOO... 

In the chloride process natural rutile ore or synthetic rutile with a Ti02-content of up to 96% is chlorinated in a fluidized bed reactor with oil-coke and chlorine. The raw TiCl4 produced is mixed with reducing agents to convert impurities, such as vanadium oxychloride, to lower valency state vanadium compounds. The titanium tetrachloride formed is then distilled yielding titanium tetrachloride in... 

Vanadium compounds (vanadic acid and vanadium chloride) have been proposed as substitutes for copper sulphide, but without much practical success. Potassium ferrocyanide and ferricyanide are also used to a certain extent. A mixture of these salts with aniline salt and potassium chlorate is printed, and the goods aged. The probable action is that the ferricyanide oxidises the aniline, and is continually regenerated from the ferrocyanide formed by the chloric acid present. Thus these salts play the part of oxygen carriers in a similar manner to the copper and vanadium compounds. In the opinion of technologists, the hlack produced by this process differs somewhat in its properties from that obtained with copper, but this may be ascribed to the presence of prussiaii blue in the former. In place of the aniline hydrochloride and potassium chlorate, a mixture of aniline sulphate and barium chlorate has recently been employed in black-printing. 

The ability of phosphines to act as both a metal oxidation states and as a 7r acceptor to relieve electron density from lower metal oxidation states explains, in part, the observation that diphosphines stabilize the +3, +1, and 0 oxidation states at the expense of the +2 oxidation state.870 Vanadium(II) diphosphine halides, [V(dmpe)2X2] (dmpe = dimethyl-dimethylphosphinoethane, X = Br or I), were prepared as side products in the synthesis of [XV(CO)2(dmpe)2].885 The structurally characterized diphosphino V11 tetrahydroborate complex, tra .s-[V(BH4)2(dmpe)2], (223) was synthesized via the reduction of similar vanadium(III) precursors.832 The reaction of a vanadium(II) chloride salt with dmpe afforded the tra s-[VCl2(dmpe)2] complex which can be alkylated with MeLi or MgMe2 to afford the organometallic trans-[V(Me)2(dm pcVJ compound, which in turn reacts with thiocyanate to form tnms -[V(NCS)2(dmpe)2].8 87 Acetonitrile or propionitrile readily displace the chlorides from trans- WCl2(dmpe)2] to form // tf/ ,v-[V( NCR)2(dmpc)2][BI>h4]2 (R = Me or Et) the acetonitrile derivative reacts with HCPh(S02CF3)2 in acetonitrile solvent to yield the hexaacetonitrile species [V(NCMe)6]2+.887... 

Indirect evidence of absorption after inhalation of vanadium in animals is indicated in studies in which vanadium was administered intratracheally. Soluble vanadium compounds that are inhaled and deposited are readily absorbed. Initial pulmonary clearance is rapid in rats. There was rapid 100% absorption of vanadium in rats receiving radiolabeled vanadyl chloride (Conklin et al. 1982). 

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