Antimony chloride-silver

Silver diethyldithiocarbamate [1470-61-7] is a reagent commonly used for the spectrophotometric measurement of arsenic in aqueous samples (51) and for the analysis of antimony (52). Silver iodate is used in the determination of chloride in biological samples such as blood (53). 

The reaction is a sensitive one, but is subject to a number of interferences. The solution must be free from large amounts of lead, thallium (I), copper, tin, arsenic, antimony, gold, silver, platinum, and palladium, and from elements in sufficient quantity to colour the solution, e.g. nickel. Metals giving insoluble iodides must be absent, or present in amounts not yielding a precipitate. Substances which liberate iodine from potassium iodide interfere, for example iron(III) the latter should be reduced with sulphurous acid and the excess of gas boiled off, or by a 30 per cent solution of hypophosphorous acid. Chloride ion reduces the intensity of the bismuth colour. Separation of bismuth from copper can be effected by extraction of the bismuth as dithizonate by treatment in ammoniacal potassium cyanide solution with a 0.1 per cent solution of dithizone in chloroform if lead is present, shaking of the chloroform solution of lead and bismuth dithizonates with a buffer solution of pH 3.4 results in the lead alone passing into the aqueous phase. The bismuth complex is soluble in a pentan-l-ol-ethyl acetate mixture, and this fact can be utilised for the determination in the presence of coloured ions, such as nickel, cobalt, chromium, and uranium. 

Metal Halides. Reacts explosively or violently with the following calcium bromide iron(III) bromide or chloride iron(II) bromide or iodide cobalt(II) chloride silver fluoride all four mercury(II) halides copper(I) chloride, bromide or iodide copper(II) chloride and bromide ammonium tetrachlorocuprate zinc and cadmium chlorides, bromides, and iodides aluminum fluoride, chloride, and bromide thallium bromide tin(II) or (IV) chloride tin(IV) iodide arsenic trichloride and triiodide antimony and bismuth trichlorides, tribromides, and triiodides vanadium(V) chloride chromium(IV) chloride manganese(II) and iron(II) chlorides and nickel chloride, bromide, and iodide.17,22"25... 

The properties of anion-exchange resins of several types have been described in detail by Kraus and Nelson 351-356) and others (557, 358). Selenium(IV), tellurium(IV), and arsenic(III) and (V) can be extracted from a variety of media 359-361). Thallium(III) and antimony(V) can be separated using the iodide and chloride forms of Dowex-1 (5(52, 363). Beryllium(II) was efficiently extracted by the carbonate form 364, 365) and chromium(III) and lead(II) by the phosphate form of AV-17 resin 366). Zinc(II) can be removed from a solution containing several metals (5(57, 368) and silver in concentrations at the 0.04-ppb level can be extracted from seawater (5(59). Cobalt(II), zinc(II), antimony(III), silver(I), and iron(III) ions have also been extracted from spiked seawater samples by anion exchange even though the actual form of the ions in the aged solution was uncertain (570). Anion resins have been modified with Trilon B (577) and with a-hydroxyisobutyronitrile (572) to increase the extraction of several trace-metal pollutants. Amberlite IRA 400 treated with the sulfonic acid derivative of dithizone can be used to concentrate heavy metals (575). 

Silver reduces the oxygen evolution potential at the anode, which reduces the rate of corrosion and decreases lead contamination of the cathode. Lead—antimony—silver alloy anodes are used for the production of thin copper foil for use in electronics. Lead—silver (2 wt %), lead—silver (1 wt %)—tin (1 wt %), and lead—antimony (6 wt %)—silver (1—2 wt %) alloys ate used as anodes in cathodic protection of steel pipes and stmctures in fresh, brackish, or seawater. The lead dioxide layer is not only conductive, but also resists decomposition in chloride environments. Silver-free alloys rapidly become passivated and scale badly in seawater. Silver is also added to the positive grids of lead—acid batteries in small amounts (0.005—0.05 wt %) to reduce the rate of corrosion. 

Determination of silver as chloride Discussion. The theory of the process is given under Chloride (Section 11.57). Lead, copper(I), palladium)II), mercury)I), and thallium)I) ions interfere, as do cyanides and thiosulphates. If a mercury(I) [or copper(I) or thallium(I)] salt is present, it must be oxidised with concentrated nitric acid before the precipitation of silver this process also destroys cyanides and thiosulphates. If lead is present, the solution must be diluted so that it contains not more than 0.25 g of the substance in 200 mL, and the hydrochloric acid must be added very slowly. Compounds of bismuth and antimony that hydrolyse in the dilute acid medium used for the complete precipitation of silver must be absent. For possible errors in the weight of silver chloride due to the action of light, see Section 11.57. 

The solution should be free from the following, which either interfere or lead to an unsatisfactory deposit silver, mercury, bismuth, selenium, tellurium, arsenic, antimony, tin, molybdenum, gold and the platinum metals, thiocyanate, chloride, oxidising agents such as oxides of nitrogen, or excessive amounts of iron(III), nitrate or nitric acid. Chloride ion is avoided because Cu( I) is stabilised as a chloro-complex and remains in solution to be re-oxidised at the anode unless hydrazinium chloride is added as depolariser. 

Miller A process for purifying and removing silver from gold by passing chlorine gas through the molten metal, covered with borax. The silver forms silver chloride, which floats to the top. Bismuth, antimony, and arsenic are eliminated as their volatile chlorides. Developed by F. B. Miller at the Sydney Mint in Australia in 1867 and soon in world-wide use. 

In the presence of a catalytic amount of an antunony(V) salt (SbCU SbFe ), generated from antimony(V) chloride and silver hexafluoroantimonate, the Beckmann rearrangement of several ketoxime trimethylsilyl ethers proceeds smoothly to give the corresponding amides or lactams in good yields . ... 

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