Dichromates halides

Nitric acid, fuming Organic matter, nonmetals, most metals, ammonia, chlorosulfonic acid, chromium trioxide, cyanides, dichromates, hydrazines, hydrides, HCN, HI, hydrogen sulflde, sulfur dioxide, sulfur halides, sulfuric acid, flammable liquids and gases... 

The indicator electrode employed in a potentiometric titration will, of course, be dependent upon the type of reaction which is under investigation. Thus, for an acid-base titration, the indicator electrode is usually a glass electrode (Section 15.6) for a precipitation titration (halide with silver nitrate, or silver with chloride) a silver electrode will be used, and for a redox titration [e.g. iron(II) with dichromate] a plain platinum wire is used as the redox electrode. 

Catalytic elfects on the thermal decomposition and burning under nitrogen of the nitrate were determined for ammonium dichromate, potassium dichromate, potassium chromate, barium chloride, sodium chloride and potassium nitrate. Chromium(VI) salts are most effective in decomposition, and the halides salts during burning of the nitrate [1]. The effect of chromium compounds soluble in the molten nitrate, all of which promote decomposition of the latter, was studied (especially using ammonium dichromate) in kinetic experiments [2],... 

Thallium compounds, 24 629-635 properties of, 24 631t Thallium dichromate, 6 538 Thallium halides, uses for, 24 636 Thallium hydrides, 24 632 Thallium hydroxides, 24 632-633 Thallium intoxication, 24 638, 639... 

In this state, chromium compounds are usually coloured yellow or red (but due to charge transfer (p. 60) and not to the presence of d electrons on the chromium ion). The only halide known is the unstable chromium(VI) fluoride CrF6, a yellow solid. However, oxide halides are known, for example Cr02Cl2 ( chromyl chloride ), formed as a red vapour when concentrated sulphuric acid is added to a chromate(VI) (or dichromate) mixed with a chloride ... 

Types of titrations for which potendometric methods of determining endpoints are particularly useful including dtrarions of halide mixtures, of various metals, of alkaloids, in non-aqneous solvents, and various titrations with oxidizing agents, such as permanganate, dichromate, iodate, and cenc sulfate. 

Chromate and dichromate are capable of displacing halide from benzylic and allylic halides. Oxidation with dichromate has been performed under traditional conditions (equation 37) with the aqueous sodium salt, or with a quaternary ammonium salt in an aptotic solvent (equation 38). Of the two procedures the first would seem to be preferable from the point of view of simplicity and safety. 

Two procedures exist for the oxidation of allylic and benzylic halides with chromate ion. In the first, the halide is heated with potassium dichromate in dry HMPA in the presence of 18-ctown-6 (equation... 

Potassium dichromate, K2Cr20 , adsorbed on silica gel (or on alumina, magnesia or Florisil) is a selective oxidant of allylic and benzylic alcohols and halides in neutral media. ... 

Bleaching based on dichromate as the oxidant has been used extensively in the past and is useful for providing solvent bleaches as the dichromate has sufficient potential (see Table 10) without the need to add halide or a silver complexing agent. Solvent bleaches are especially useful for black-and-white reversal systems where they are still used extensively. 

Acids and bases have been standardized coulometrically with standard deviations of 0.003% halides by generation of silver ions to 0.005% potassium dichromate by generation of iron to 0.003% and conditions established under which... 

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