Vanadous oxide

Vanadium is beneficial and possibly essential for humans. It is certainly essential for a number of organisms. Vanadate (oxidation state V) and its derivatives are phosphate analogues, showing both ground state and transition state analogy (both structural and electronic) with phosphorus compounds. The analogy of five-coordinate vanadium compounds with the transition state of phosphate ester hydrolysis is well documented, and explains why so many vanadium compounds are potent inhibitors of phosphatases, ribonucleases and ATPases. 

In 1927 J. W. Marden and M. N. Rich of the research staff of the Westinghouse Lamp Company obtained metallic vanadium 99.9 per cent pure by heating a mixture of vanadic oxide, metallic calcium, and calcium chloride in an electric furnace for an hour at a temperature of about 1400° Fahrenheit. When the resulting mass was cooled and stirred into cold water, beads of pure metallic vanadium separated out (35). 

Cone, aqua ammonia in the cold dissolves carbamate from the commercial carbonate, and it converts the hydrocarbonate into normal carbonate-either by removing half its carbonic monohydride, or by combining with it and with water. If the commercial carbonate be digested with a sat. soln. of ammonia in a closed vessel at 20° to 25°, this salt slowly dissolves, and the soln., on cooling, deposits crystals of ammonium carbamate and a little normal carbonate (NH3)3H20(C02)2-j-NH3 =H20+2C02(NH3)2. C. Arnold has tabulated the solubilities of the freshly precipitated carbonates and hydroxides of most of the common metals in sat. soln. of potassium and ammonium carbonates. A. Ditte studied the action of soln. of ammonium carbonate on vanadic oxide. 

Vanadium Oxymonobromide, VOBr, is prepared by the decomposition of vanadyl dibromide, VOBr2, in vacuo at 360° C. It forms violet, octahedral crystals, density 4-000 at 18° C. On being heated in vacuo at 480° C. it yields vanadium tribromide and vanadous oxide, V203. It is almost insoluble in water and the usual organic solvents.7... 

Vanadium Oxytribromide, VOBr3, is produced when pure, dry bromine is passed over vanadous oxide, V2Os, heated to redness. Yellowish-white vapours are evolved which condense to a deep red, hygroscopic liquid, density 2-9673 at 0° C. It decomposes slowly at ordinary temperatures into vanadyl dibromide and bromine, but distils without decomposition at 130° to 136° C. under 100 mm. pressure. It is much less stable than vanadyl dibromide, VOBra.a... 

Iodine does not react with finely divided vanadium,4 nor with the nitride, VN, or vanadous oxide, V203.5 Anhydrous vanadium triiodide has not as yet been prepared. 

Hypovanadic oxide is most conveniently obtained by heating any of the foregoing hydrates in the absence of air. It is also formed (a) from vanadium pentoxide by heating in admixture with the trioxide, carbon, or oxalic acid,6 and (b) from vanadous oxide by prolonged exposure to air.7... 

V02.V205.4H20 results on the exposure of vanadous oxide, V203, to air for several months.3... 

With hydrobromic acid and hydriodic acid reduction may proceed to the trivalent state,9 and it has been shown that in the presence of acetic acid, hydrazine also produces vanadous oxide, V203, instead of hypovanadic oxide, V02 10... 

Biiltemann 2 observed that vanadium ammonium alum separates out in blue crystals from a solution containing sulphuric acid, but from solutions containing a weak acid, or from neutral solutions, red crystals are obtained. (The chromium alums can also be prepared in differently coloured modifications.) The analytical data, melting-point, electrical conductivity, rate of efflorescence, and general behaviour of both kinds of crystals are identical, so that it is difficult to ascribe different constitutions to them. Meyer and Markowitz3 have shown that both forms separate out when the molecular proportion of sulphuric acid in the solution is less than that theoretically required, and attribute the red colour to the presence of traces of vanadous oxide, V203, or its hydroxide, V(OH)3. Vanadium rubidium and vanadium ciesium alums behave in the same way. A vanadium guanidine alum has also been prepared.4... 

SYNS VANADIC OXIDE VANADIUM OXIDE VANADIUM TRIOXIDE... 

VANADIC ACID, AMMONIUM SALT see ANY250 VANADIC ACID, MONOSODIUM SALT see SKPOOO VANADIC ACID, POTASSIUM SALT see PLK810 VANADIC(II) ACID, TRISODIUM SALT see SIY250 VANADIC ANHYDRIDE see VDUOOO VANADIC OXIDE see VEAOOO VANADIO, PENTOSSIDO di (ITALIAN) see VDUOOO VANADIUM see VCPOOO... 

B. Redox decomposition of monoalkyl ester of dimeric vanadate, ROVO2-O-V03 , accompanied by two rapid successive one-electron transfers. Then, no free radical species are expected, and the products should be the carbonyl compound and VO. This mechanism has not yet been established for vanadate oxidations. 

Synonyms Vanadic (II) acid trisodium salt sodium vanadate sodium vanadate oxide trisodium ortho vandata Amnaniuzn vanadate vanadic acid anznonium salt... 

Westinghouse Lamp Co. by heating a mixture of vanadic oxide, metallic Ca and CaCl2 in... 

Vanadium Trioxide. Vanadium sesquioxide vanadic oxide. OjV2 mo] wt 149.90. V 67.98%, O 32.02%. VjOj, Prepd by reduction of V20, with hydrogen or carbon monoxide. 

Vanadic oxides attack the metal surface by dissolving the normally protective oxide layer and assisting in the transport of oxygen to the pure metal surface. 

Damage is generally associated with the combined presence of vanadium (arising as a porphyrin in the fuel), sodium (derived from sodium chloride), sulfur (from the fuel), and oxygen. During combustion, vanadic oxides and sodium sulfate may condense as low melting vanadyl vanadates, which permit the rapid dissolution of surface oxides and metal alkali. The processes occur very rapidly. Oxide dissolution can appear to be synonymous with metallic loss (Johnson et al. 1975). 

Vanadic acid (H3VO4), tris (2-methylpropyl) ester. See Tri isobutyl vanadate Vanadic anhydride. See Vanadium pentoxide Vanadic oxide. See Vanadium trioxide Vanadium... 

Synonyms Vanadic oxide Vanadium oxide Vanadium sesquioxide... 

Assamoi, A. Hamon, M. Chastagnier, M. Chaigneau, M. Vanadate oxidation of quinine and some analogs. Application to the determination of mefloquine, a new antimalarial drug. Talanta 1987, 34, 1015-1020. 

Nitric acid (s. a. under NH4-vanadate) Oxidative ring opening of isocycles... 

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