260 Chloriodide of Platinum. 



The chloriodide of platinum weighed 30.28 grammes. As the 

 iridium separated from the platinum by solution, weighed 0.095 

 grammes, the platinum in the 30.28 grammes of chloriodide was 10. 

 000 — 0.095 = 9.905 grammes. The chloriodide of platinum is 

 then composed of 



Chlorine and Iodine, - - - 20.375 67.289 

 Platinum, 9.905 32.711 



30.280 100.000 



Analysis of Chloriodide of Platinum. 



(a) One gramme of chloriodide of platinum was mixed with dry 

 carbonate of potassa in a glass tube, and covered to some depth with 

 the same. It was then decomposed by heat, chloride and iodide of 

 potassium being formed. 



(b) The- contents of the tube (a) were dissolved in water, except 

 the spongy platinum, which was separated by decantation, Avashing, 

 and filtration upon a double filter of equal weights as in the preceding 

 analyses. The dry platinum weighed 0.315 grammes. 



(c) The decanted and filtered liquid (b) was treated with nitric 

 acid, to drive off the carbonic acid from the carbonate of potassa. — 

 A yellow tint was given to the liquid by chloride of iodine, which 

 was formed by the nitric acid liberating its elements from their pre- 

 vious combinations. The odor of iodine was perceived as long as 

 carbonic acid was evolved. There was thus a loss of iodine and 

 perhaps also of chlorine. 



(d) Nitrate of silver was added to the liquid (c) to throw down 

 the chlorine and iodine, as chloride and iodide of silver. An abun- 

 dant yellow precipitate fell, and this was separated fi^om the color- 

 less solution by decantation, washing and filtering. The precipitate 

 was washed on the double filter as long as the washings gave any 

 cloudiness to muriatic acid, (nitrate of silver having been used in 

 excess as a precipitant.) 



(e) The moist precipitate on the filter (d) was digested in ammo- 

 nia, to dissolve the chloride of silver, and afterwards ammonia was 

 made to pass through the precipitate as long as it left any residue by 

 evaporation. 



The ammoniacal solution of chloride of silver was evaporated to 

 dryness, and the chloride fused and reduced. 



The silver from the chloride weighed 0.20 grammes. 



