Silver molybdate

Other Uses. Photochromic glass contains silver chloride (80) and silver molybdate [13765-74-7] (81) (see Chromogenic materials). An apparatus coated with silver nitrate has been described for the detection of rain or snow (82). Treatment with silver-thiosulfate complex has been reported as dramatically increasing the post-harvest life of cut carnations (83). Silver sulfate has been used in the electrolytic coloring of aluminum (84). Silver sulfate also imparts a yellowish red color to glass bulbs (85). 

Normal Silver Molybdate, Ag2Mo04, is obtained as a yellowish-wiiite flocculcnt precipitate by double decomposition of solutions of silver nitrate and normal potassium molybdate it may be obtained in colourless erj-stals by slowiy evaporating strongly ammoniacal solutions of silver nitrate and molybdie acid. It is readily fusible, is slightly soluble in water, and is soluble in nitric acid, potassium cyanide, and ammonia. ... 

More recent developments concern the photochromic borosilicate glasses containing silver-molybdate and tungstate [45] or copper- and cadmium-halides [46,47] instead of silver halides. The glasses have a similar spectral sensitivity but show a stronger proportionality between light intensity and darkening. 

Butadiene and other alkadienes can be oxidized to furans using copper catalysts (CuC /CuCl) <8lUSP426842l>, silver molybdate/AI2O3 <81USP4293444>, or PdCl2/In(OH)3 in the presence of AIBN... 

Fig. 6 SEM images of silver molybdate nanowires (A), AgCl nanowires (B), and Ag/AgCl composites (C). Reprinted from ref. 6, Copyright (2012), with permission from Elsevier.

Nagarju G, Chandrappa GT, Livages J. Synthesis, characterization of silver molybdate nanowires, nanorods and multipods. Bull Mater Sci 2008 31(3) 367-71. 

Arsenites may also be determined by this procedure but must first be oxidised by treatment with nitric acid. Small amounts of antimony and tin do not interfere, but chromates, phosphates, molybdates, tungstates, and vanadates, which precipitate as the silver salts, should be absent. An excessive amount of ammonium salts has a solvent action on the silver arsenate. 

Discussion. Molybdates [Mo(VI)] are quantitatively reduced in 2M hydrochloric acid solution at 60-80 °C by the silver reductor to Mo(V). The reduced molybdenum solution is sufficiently stable over short periods of time in air to be titrated with standard cerium(IV) sulphate solution using ferroin or /V-phenylanthranilic acid as indicator. Nitric acid must be completely absent the presence of a little phosphoric(V) acid during the reduction of the molybdenum(VI) is not harmful and, indeed, appears to increase the rapidity of the subsequent oxidation with cerium(IV) sulphate. Elements such as iron, copper, and vanadium interfere nitrate interferes, since its reduction is catalysed by the presence of molybdates. 

H. 8-Hydroxyquinaldine (XI). The reactions of 8-hydroxyquinaldine are, in general, similar to 8-hydroxyquinoline described under (C) above, but unlike the latter it does not produce an insoluble complex with aluminium. In acetic acid-acetate solution precipitates are formed with bismuth, cadmium, copper, iron(II) and iron(III), chromium, manganese, nickel, silver, zinc, titanium (Ti02 + ), molybdate, tungstate, and vanadate. The same ions are precipitated in ammoniacal solution with the exception of molybdate, tungstate, and vanadate, but with the addition of lead, calcium, strontium, and magnesium aluminium is not precipitated, but tartrate must be added to prevent the separation of aluminium hydroxide. 

Many heavy metals react with dithiol to give coloured precipitates, e.g. bismuth, iron(III), copper, nickel, cobalt, silver, mercury, lead, cadmium, arsenic, etc. molybdate and tungstate also react. Of the various interfering elements, only arsenic distils over with the tin when a mixture is distilled from a medium of concentrated sulphuric acid and concentrated hydrobromic acid in a current of carbon dioxide. If arsenic is present in quantities larger than that of the tin it should be removed. 

In the last 20 years, new sulphide, sulphate, molybdate, halide, etc., based compositions have been obtained in the glassy state (Ingram, 1987). They have much higher ionic conductivity than most oxide glasses at ambient temperature, e.g. from 10 to 10 S cm in the case of some lithium or silver conducting glasses (Fig. 4.1(h)). 

Mechanisms There is a derth of knowledge about the mechanisms operative in selective oxidation reactions. The only exceptions are the reactions of ethylene to ethylene oxide on supported silver catalysts and of propylene to acrolein on bismuth molybdate type catalysts. For the latter, it is well established through isotopic labeling experiments that a symmetric allyl radical is an intermediate in the reaction and that its formation is rate-determining. Many studies simply extrapolate the results substantiated for this case to other reactions. New ideas on mechanisms are presented by Oyama, et oL, Parmaliana, et aL, and Laszlo. 

I discovered tellurium in 1789 in Born s so-called molybdic silver. The following year I mentioned it verbally to Mr. Estner and after some time sent... 

---