Cuprous chromate

The mechanism and rate of hydrogen peroxide decomposition depend on many factors, including temperature, pH, presence or absence of a catalyst (7—10), such as metal ions, oxides, and hydroxides etc. Some common metal ions that actively support homogeneous catalysis of the decomposition include ferrous, ferric, cuprous, cupric, chromate, dichromate, molybdate, tungstate, and vanadate. For combinations, such as iron and... 

Little work has been carried out on the mechanism of inhibition of the corrosion. of copper in neutral solutions by anions. Inhibition occurs in solutions containing chromate , benzoate or nitrite ions. Chloride ions and sulphide ions act aggressively. There is evidence that chloride ions can be taken up into the cuprous oxide film on copper to replace oxide ions and create cuprous ion vacancies which permit easier diffusion of cuprous ions through the film, thus increasing the corrosion rate. 

Starting with examples of Mechanism 10 in inorganic chemistry, one may cite the oxidation of cuprous thiosulfate by ferric, vanadate, molybdate, and chromate ions (38). 

Other typical reagents generated for coulometric titrations are hydrogen and hydroxyl ions, redox reagents such as ceric, cuprous, ferrous, chromate, ferric, manganic, stannous, and titanous ions, precipitation reagents such as silver, mercurous, mercuric, and sulfate ions, and complex-formation reagents such as cyanide ion and EDTA [8-10]. 

Copper Chromates.—Both cuprous and cupric chromates are known. The latter forms an ammoniacal salt, 2CuCrO4.CuO.10NH3, which is obtained on precipitating a green solution of basic cojjper chromate in ammonia by means of alcohol, as dark green needles which are unstable in air. The salt, CuCrO. lNHj, also exists. ... 

Silver Oxide Silver Chromate Barium Peroxide Lead Chromate Cuprous Oxide Barium Chromate... 

J. F. Persoz obtained cuprous chromite, CuCr02, by calcining cupric chromate in a crucible exposed to the reducing action of the furnace gases, and extracting the product with hydrochloric acid and L. and P. Wohler obtained it by heating one of the basic cupric chromites with an excess of cupric oxide above 900°, and... 

K. Fischbeck and E. Einecke found that the cathodic polarization of ferrous, cuprous, calcium, and magnesium chromites produces chromic acid, whilst the other chromites are unaffected, and natural chrome ironstone behaves in a like manner, but other commercial chromites are reduced on cathodic polarization, and yield chromic acid on anodic polarization. Chromites behave as an intermediate electrode. 0. Unverdorben observed that chromyl fluoride, prepared by heating a mixture of fluorspar, lead chromate, and sulphuric acid, when passed into water, furnishes an aq. soln. of this oxide. The soln. was treated with silver nitrate, and the washed precipitate of silver chromate decomposed by hydrochloric acid. A. Mans said that anhydrous sulphuric acid or fuming sulphuric acid is not suited for the preparation because of its volatilization with the chromyl fluoride. 

Described in late eighteenth century sources as a combination of copper and tartar ( cuprous tartar - copper tartrate A Practical Treatise (1795), de Massoul (1797)), then as copper and arsenic (Merimee, 1830), finally a mixture of lead chromate and Prussian blue (Salter, 1869) the latter stated that Prussian blue would he destroyed by lead chromate and was better compounded... 

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