Tetraphenylarsonium chloride precipitant

Tetraphenylarsonium chloride (107,108) has also been used for the precipitation of the perchlorate ion in gravimetric analysis. 

Determination as the tetraphenylarsonium compound Discussion. Any ions forming a precipitate with tetraphenylarsonium chloride (e.g. MnO, ClOj, Br , I-, I03 and SCN-) will interfere. Difluorophosphates give slight interference which can be overcome by boiling the solution for a few minutes to hydrolyse difluorophosphate the hexafluorophosphate ion is not affected by this treatment. 

The exchange of Mo between the anions Mo(CN)g and Mo(CN)g has been investigated by the isotopic method ( Mo) and the separation methods (a) precipitation of Mo(CN)g with either ethanol or cadmium ions, and (b) precipitation of Mo(CN) with tetraphenylarsonium chloride. Complete exchange was observed by Wolfgang even with reactant concentrations 5x10 M. An estimate of the rate coefficient at 2 °C of >10 l.mole . sec has been sug-geMd. 

Procedure To the sample which contains 20-300 /xg of pertechnetate in 5-20 ml of solution, are added potassium perchlorate solution (2 ml, 1 mg KCIO per ml) and enough NaCl to make the solution approximately 1 M. The solution is heated and neutralized with ammonia. Pertechnetate is precipitated with aqueous 5 % tetraphenylarsonium chloride reagent. The precipitate is filtered, washed and dried, and a 2-mg portion is mixed with potassium bromide (300 mg). The mixture is pressed to form a clear disc by the usual technique. The infrared spectrum is recorded between 10 and 12 /x. The peak absorption is measured at 11.09 /X by the base-line technique. 

The most popular method involves weighing of the precipitate in the form of tetraphenylarsonium pertechnetate . Precipitation is carried out from neutral or alkaline solution at pH 8-9 by adding an excess of tetraphenylarsonium chloride (CgH5) AsCl. Since the precipitated salt is slightly soluble the total volume of the solution is kept to a minimum. 

Disodium tellurapentathionate, tetraphenylarsonium chloride, and potassium 2,2-dicya-noethenediselenolate reacted in aqueous methanol to precipitate tetraphenylarsonium bis[2,2-dicyanoethenediselenolato]tellurate(2-J. This compound melted at 160-162° after recrystallization by dissolution in a small volume of pyridine and cautious addition of isopropanol2. 

The uranyl ion, (U02), forms yellow azido complexes that are stable in dilute (0.01 M) aqueous solutions in the presence of excess azide a cation structure [(U02)(N3)] has been established and was used in the analysis of uranium [137,138]. The anion tetraazido complex has been isolated as the tetraphenylarsonium salt, [As(Ph)4]2 [(U02)(N3)4], by admixing a solution of 1 g uranyl nitrate in 2 N nitric acid in nitrogen environment to a solution of 7 g sodium azide. At 80°C the red solution was precipitated with tetraphenylarsonium chloride to obtain yellow crystallites that decomposed at 171°C [139]. 

The tetraphenylarsonium salt of tetraazidoaurate(III) is made from 2.5 mmole potassium chloroaurate, KAuCU, which is dissolved in a small quantity of water. One hundred mmole of sodium azide is added to obtain a red solution. After filtering, tetraphenylarsonium chloride is added to precipitate the orange complex. It is recrystallized from acetone-water, or methylene chloride-hexane mixtures [139]. The colorless tetraphenylarsonium salt of diazidoaurate(I), [Ph4As] [Au (N3)2], is obtained by reacting a suspension of freshly prepared gold monochloride, AuCl (0.2 g = 0.9 mmole), and sodium azide (1.5 g = 23 mmole) in water-wet methylene chloride. Upon addition of... 

Tetraphenylarsonium chloride hydrate [507-28-8] M 418.8, m 258-260", 261-263". A nentralised aqueous solution is evaporated to dryness. The residue is extracted into absolnte EtOH, evaporated to a small volnme and precipitated by addition of absolute Et20. It is again dissolved in a small volume of absolute EtOH or ethyl acetate and re-precipitated with Et20. Alternatively, it is purified by adding cone HCl to precipitate the chloride dihydrate. Redissolve in water, neutralise with Na2C03 and evaporate to dryness. The residne is extracted with... 

Tetraphenyl phosphonium chloride may also be.used to precipitate tin. The solution should be 0.1 -1. OM in HCl and 3, 0-3.5M in NaCl, but the interfering species are essentially the same as with tetraphenylarsonium chloride.. ... 

The complex anion hexaazidorhodate(III), [Rh (N3)6] is known as tetraphenylarsonium salt [139] and as tetrabutylammonium salt [162]. For preparation of the former, see Table IX. The tetrabutylammonium hexa-azidorhodate(III) is obtained from the [RhCle] " complex by ligand exchange 0.2 g Na3RhCl6 I2H2O is dissolved in 25 ml water and added to a solution of 1.5 g sodium azide in 50 ml water. The mixture is kept at 40°C for 1 hr and then precipitated with 1 g tetrabutylammonium bromide. The faintly red crystals are washed with alcohol and, from a methylene chloride solution, reprecipitated with ether [162]. 

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