Molybdates


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Molybdates

 

salts of molybdic acids. Two types of molybdates are known: normal molybdates (salts of molybdic acid, H2MoO4) and polymolybdates (salts of isopolymolybdic acids). All normal molybdates, except the molybdates of alkali metals and magnesium, are poorly soluble in water. The most important soluble molybdate is Na2MoO4, which is used in the manufacture of dyes and varnishes; soluble molybdates are widely used as trace fertilizers.

Naturally occurring calcium, iron, and lead salts are among the most valuable poorly soluble molybdates. Calcium molybdates are also used to introduce molybdenum in the manufacture of alloy steels. Examples of isopolymolybdates include sodium di-, tri-, and tetra-molybdates, Na2Mo2O7, Na2Mo3O10, and Na2Mo4O13, respectively. Polymolybdates such as sodium paramolybdate, Na6Mo7O24 · xH2O, and ammonium paramolybdate, (NH4)6Mo7O24 · xH2O, have acquired wide practical significance. The latter is usually the final product in the processing of molybdenum concentrates and is widely used as a reagent.

A. N. ZELIKMAN

References in periodicals archive ?
3], or, in other cases, involve the formation of insoluble salts such as phosphate, molybdate, and silicate with zinc or calcium ions due to the prevailing alkaline conditions at the cathode.
Sodium molybdate is well suited as a non-toxic, anodic (pitting) corrosion inhibitor of steel (Rey et al.
Korobov, VI, Loshkarev, YM, Kozhura, OV, "Cathodic Treatment of Galvanic Zinc Coatings in Solutions of Molybdates.
Molybdates are known to passivate a steel substance by forming a ferrous molybdate layer.
Modern pigments include modified zinc phosphates and various proprietary non-toxic pigments, such as phosphates, molybdates, silicates, borates, and ion exchange.
Inorganic pigments include carbon black, titanium dioxide, iron oxide, lead chromates and molybdates, mixed metal oxides, chromium oxide, and ultramarines.
Organic-based products will remain the largest type in value terms, although molybdates and silicates will experience faster growth.
In addition, readers get a close look at the hydrothermal synthesis of zeolites, fluorides, sulfides, tungstates, and molybdates, as well as native elements and simple oxides.