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Tungstic Acid Appears

A white dihydrate, WO3.2H2O. With bases, both hydrates produce the same series of salts, and the first appears to be the true acid, tungstic acid, H2WO4, whilst the second is the hydrate, HjWOi.HaO. Both are insoluble in water, but colloidal forms of the acid e.xist. Several other hydrates have been described, but except in the case of the complex hydrate known as metatungstic acid (see p. 238) their existence has not been established. [Pg.205]

Ammonium Tungstates.— The normal salt cannot be obtained by dissolving tungstic acid in aqueous ammonia, since on concentration ammonia is lost and an acid salt remains. That the normal tungstate is present in solution would appear evident from the fact that calcium chloride precipitates the normal calcium tungstate. It may be obtained as a white mass by the addition of hydrated tungstic acid to liquid ammonia. The normal tungstate is very soluble in water and readily loses ammonia. [Pg.211]

The hexafluorides of molybdenum and tungsten arc volatile liquids (respective b.p. 35.0° and 19.6°), readily hydrolysed to molybdic and tungstic acids. WClg is a solid. The metals form oxide chlorides, MO.,Cl2. Chromyl chloride, familiar as a distinguishing test for a chloride, appears as a yellow distillate on heating a chloride with KgCrgO and concentrated H2SO4 ... [Pg.469]

Pertungstic acid and its derivatives are little known compounds formed by the action of hydrogen peroxide on tungstic acid or the tungstates, Usually at the boiling temperature. They are easily soluble, unstable, and difficult to purify. The valence of tungsten in these compounds appears to be higher than six. [Pg.289]

Oxygen-containing Heterocycles Three-membered Rings. - The addition of oxygen to double bonds remains the most common method for epoxide synthesis, and several new variations on that theme have appeared this year. Thus, alkenes are converted into epoxides using a solution of elemental fluorine in an acetonitrile/water mixture with complete retention of olefin stereochemistry.1 Prat and Lett have re-examined the use of tungstic acid catalysed epoxidation in an attempt to define the scope and synthetic utility of the process. They have shown that reactivity increases with the nucleophilicity of the double bond and... [Pg.547]


See other pages where Tungstic Acid Appears is mentioned: [Pg.291]    [Pg.291]    [Pg.304]    [Pg.129]    [Pg.976]    [Pg.5]    [Pg.195]    [Pg.241]    [Pg.245]    [Pg.254]    [Pg.260]    [Pg.265]    [Pg.271]    [Pg.592]    [Pg.450]    [Pg.64]    [Pg.143]    [Pg.173]    [Pg.12]    [Pg.369]    [Pg.17]    [Pg.180]    [Pg.649]    [Pg.1060]    [Pg.1631]    [Pg.649]    [Pg.523]    [Pg.4120]    [Pg.159]   


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Tungstic acid

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