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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.


References in periodicals archive ?
The second solution of lower reactant was prepared by adding ammonium molybdate and ammonium nitrate each weighing 817 mg to 80 mL of distilled water.
Waring, "Control and application of domain wall motion in gadolinium molybdate," Ferroelectrics, vol.
Ittyachen, "Growth and characterization of rare-earth mixed single crystals of samarium barium molybdate," Bulletin of Materials Science, vol.
Wilcox, GD, Gabe, DR, Warwick, ME, "The Development of Passivation Coatings by Cathodic Reduction in Sodium Molybdate Solutions.
Aqueous molybdenum, cobalt and platinum solutions were prepared from ammonium heptamolybdate (AHM, Merck), sodium molybdate dihydrate (SoMo, Merck), cobalt (II), nitrate hexahydrate (CoNi, Sigma), cobalt (II) chloride hexahydrate (CoCl, Aldrich), cobalt (II) acetate tetrahydrate (CoAc, Aldrich) and hexachloroplatinic acid (Sigma); deionized water (Milli Q quality, 18.
It is generally accepted that two kinds of coordination structures of surface molybdate species (tetrahedral and octahedral) exist on the [gamma]-[Al.
Although the use of aqueous molybdate solutions is debatable, Bergwerff et al.
52), (53) In this experiment, it could be clearly appreciated and confirmed that the protective layer is a molybdate film that dissolved as corrosion continued over time (see Fig.
III]-Mo compound prevents reaction of molybdate with further phosphate generated from the hydrolysis of labile organic phosphates (e.
Szenicsite joins ferrimolybdite, lindgrenite, powellite and wulfenite as a simple molybdate.
1] region is due to the molybdate ion while the medium band near 3400 [cm.