L.—The double platinic and cupric iodides of substituted ammonium bases

Rasik Lal Datta
1913 Journal of the Chemical Society Transactions  
THE double platinic iodides of the alkali and alkaline earth metals were first prepared by Lassaigne (Anmlen, 1833, 8, 185 ) by dissolving platinic iodide in solutions of the respective metallic iodides. Later, Mather and Platt (Amer. Chem. J., 1834, 27, 257) prepared potassium platini-iodide by mixing a solution of platinic chloride with a slight excesa of potmsium iodide, evaporating to dryness on the water-bath, and extracting with a mixture of alcohol and ether so long as thO colour was
more » ... unicated to the washing liquid. It is evident that Mather and Platt obtained the compound in a 427 highly impure state, largely contaminated with potassium chloride, since by this interaction much potassium chloride is formed which cannot entirely be washed out by the solvent used by them. Kane (PhiLMag., 1833, 2, 198) attempted to prepare ammonium and potassium platini-iodides by treating pulverised potassium iodide and ammonium iodide respectively with platinic chloride solution and washing the precipitates obtained with ether. His method, however, did not lead t o the preparation of pure compounds, and he necessarily failed t o arrive a t a definite conclusion. The following double iodides have been directly obtained as black, crystalline precipitates by adding platinic chloride to sohtions of alkali and substituted ammonium iodides, but it has been found that double plaiinic iodides of sodium and alkaline earth metals could not be precipitated similarly owing t o their extreme solubility. Rubidium Platini-iodide. This salt is not 6 0 soluble as the potassium salt, as was to be expected from a comparison of the solubility of the platinichlorides. Hence it was obtained from a tolerably concentrated solution as a black, crystalline precipitate. It is moderately soluble in water : 0.3321 gave 0.4884 AgI. 1=67*73. Rb2Pt16 requires I = 67-55 per cent. Caesium Pla tini-iodid e. This is a sparingly soluble salt, and was obtained by precipitation 0-1037 gave 0'1251 A@. I=62*99. It is a black powder, only sparingly soluble in water, forming a f aintly-coloured solution. Its sparing solubility is quite in keeping with the intense electropositiveness of the metal, and it is one of the most stable platini-iodides. of dilute solutions : Cs$?tI6 requires I= 62.36 per cent. M e thylammonium Pla tini-iodid e. This was obtained as a black precipitate, which was washed and 0.2239 gave 0.0424 Pt. Pt= 18.92. 0.1021 " 0'1416 AgI. 1=74*96. 2CH,N,H2Pt16 requires Pt = 19.09 ; I = 74.63 per cent. This salt is freely soluble in water, but less so than the corresponding salt with ammonium iodide, forming a deep red solution. dried in the desiccator over sulphuric acid :
doi:10.1039/ct9130300426 fatcat:pvdqgpsi5zgrlbrlytrlttcfgu