Chromium iodate

According to Table 11.4, Ksp = 5.0 X 10 6 for chromium(III) iodate in water. Estimate the molar solubility of the compound. 

In order to balance mineral intake, the following minerals were used in place of the usual mineral mix (% of diet) potassium chloride, 0.32 magnesium oxide, 0.084 manganous carbonate, 0.0123 ferric nitrate, 0.021 zinc carbonate, 0.0056 cupric carbonate, 0.0011 potassium iodate, 0.0004 sodium selenite, 0.00003 chromium potassium sulfate, 0.00193. 

Ganescu et al. used thiocyanato Cr(III)-complexes in the titrimetric and spectrophotometric determination of dipyridamole [16]. For titrimetric analysis of the drug (1.36-27.2 mg), sample solutions (25-50 mL) were acidified with hydrochloric acid and treated with excess of a 3% solution of ammonium dianilinetetrakis (thiocyanato) chromium (III) in aqueous 25% ethanol. The red-violet precipitate was collected and washed, decomposed with NaOH, and the mixture again acidified. The liberated thiocyanate was titrated with potassium permanganate, potassium bromate, or potassium iodate. 

A simple and rapid method for the iodometric determination of microgram amounts of chromium(ni) in organic chelates is based on the oxidation of chromium(III) with periodate at pH 3.2, removal of the umeacted periodate by masking with molybdate and subsequent iodometric determination of the liberated iodate . Iodometric titration was also used for determination of the effective isoascorbate (see 2) concentration in fermentation processes . The content of calcium ascorbate can be determined with high sensitivity by complexometric titration with edta, which is superior to iodometry. The purity of /3 -diketonate complexes of Al, Ga, In and Ni was determined by complexometric titration with edta at pH 5.5-3, with RSD < 0.01 for determining 5-30% metal ion. Good analytical results were obtained by a similar procedure for the metal content of 15 lanthanide organic complexes. ... 

Chromium lodate, Cr(I03)g, is formed as a brown precipitate by the addition of sodium iodate to a solution of chromic chloride. ... 

Colour systems suitable for use in the spectrophotometric method may also be formed in redox reactions. Some examples of such reactions are the oxidation of Mn(II) to Mn04" or Cr(III) to Cr04, oxidation of dimethylnaphthidine with vanadium(V) or chromium(VI), oxidation of o-tolidine with cerium(lV) or with chlorine. Examples of oxidation reactions are also the iodide methods, in which iodide ions are oxidized with bromine to give iodate ions which, in turn, react with the excess of iodide anions to form free iodine (see Chapter 25). A colour effect of reduction also occurs, for example, in determinations of Se and Te in the form of coloured sols produced in the reduction of Se(lV) or Te(IV) to their elementary forms. 

EXPLOSION and FIRE CONCERNS flammable in the form of dust when exposed to heat or flame when heated or on contact with acid or acid fumes, it emits highly toxic fumes dangerous when water solutions of arsenicals are in contact with active metals such as iron, zinc, aluminum flammable by chemical reaction with bromates, chlorates, iodates, peroxides, lithium, silver nitrate, nitric acid, potassium permanganate, chromium trioxide, chlorine trifluoride, chlorine oxide, bromine trifluoride, bromine pentafluoride, bromine azide use foam, carbon dioxide, or dry chemical for firefighting purposes.. 

Iodine, 72, 293-295, 333, 452,579 Iodine-Dimethyl sulfoxide, 295 Iodine-Potassium iodate, 296 Iodine-Pyridine N-oxide, 296 lodine-Pyridine-Sulfur dioxide, 296 Iodine azide, 297 Iodine bromide, 297 lodoacetonitrile, 494 a-lodo acyl chlorides, 116 o-Iodoanisole, 130 lodobenzene, 130, 443 7r-(Iodobenzene)chromium tricarbonyl, 104 lodobenzene diacetate-Trimethylsilyl azide, 297... 

J. Sand and F. Grammling measured the velocity with which the violet hexahydrate Uberates iodine from a mixture of potassium iodide and iodate, and found the results to be in agreement with the assumption that the molecule is Cr.2Cl0.12H2O, and not [Cr(H20)e]C33. H. W. Fischer found that the solubility of chromium hydroxide in an aq. soln. of green chromic chloride is not directly proportional to the cone, of the latter. A basic chloride is probably formed. From a soln. of chromium hydroxide in aq. chromic chloride, the former cannot be precipitated either by the addition of electrolytes or by the action of heat part of it is supposed VOL. XI. 2 0... 

I. Walz obtained some iodate by the action of chromic acid on iodine. H. S. Fry treated chromium trioxide with acetyl iodide and obtained only iodine. There was no evidence of the formation of chromyl iodide. 

Inorganic anions such as iodide, iodate, nitrate, and chlorate have been determined on the basis of redox reactions. Iodides have been determined by their reaction with chromium(vi) in an acidic medium. The unreacted Cr is then extracted into MIBK from a 3 M HCl solution. The iodide concentration is quantitatively related to the increase of the Cr atomic signal in aqueous solution or the decrease of the Cr signal in the organic phase. Selenium(iv) is reduced by iodide to elemental selenium. The atomic absorption signal of selenium is then measured in the selenium precipitate. 

Until comparatively recently, the only reported stable inorganic hydrosols were primarily sols of elements such as gold, sulphur, selenium, etc. and compoimds such as silica, lead iodate, silver halides, etc. A considerable amount of attention is now being paid, however, to the preparation of mono-dispersed hydrous metal oxides, which are chemically considerably more complex than other crystalline or stoichiometrically well-defined materials and are of interest as potential catalysts. Examples include the hydrous oxides of chromium and aluminium (spheres) and copper and iron (polyhedra) with particle sizes < 1 pm. One manufacturing procedure consists of ageing aqueous... 

Alkali ferricyanides oxidize acid solutions of diethylaniline and other aromatic amines, as well as certain monoazo dyestuffs a change of color results and ferrocyanide is formed. This reversible redox reaction, proceeds very slowly and incompletely. However, if the ferrocyanide ions are removed as insoluble white zinc ferrocyanide, the oxidation proceeds rapidly. This acceleration is a result of raising the oxidation potential of ferricyanide ions through removal of ferrocyanide ions. The white zinc ferrocyanide is deeply tinted by adsorption of the colored quinoidal oxidation products of the amines, and thus affords a sensitive test for zinc. The test is especially useful in the presence of chromium and aluminum. It can also be used in other instances provided no other cations are present, which form colored precipitates with potassium ferrocyanide (Co+, Ni+, Fe+, Mn+ , Cu+ ). Traces of iron, which in practice are always to be reckoned with, do not interfere with the zinc test. Anions which oxidize the amines must be absent, e.g., permanganate, chromate, vanadate, persulfate, iodate. 

Ni(HC03)2, CuS, chromium(ni) iodate, potassium hydrogen phosphate... 

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