198 Mr. Kane's Analysis of some Combinations of Platina : 



Mr. Kane prepared the iodide of potassium and platina, by 

 adding an excess of the former in fine powder to a strong solu- 

 tion of permuriate of platina ; effervescence took place. Some 

 aether was immediately poured on the mass, and the whole 

 agitated for a few minutes; a black powder was formed, which 

 when separated by the filter was the double iodide, mixed with 

 some chloride of potassium. This double salt, when pure, 

 is very soluble in water, the solution is of a magnificent claret 

 colour ; it is not decomposed by evaporation, but yields a soft 

 crystalline mass; the form of the crystal could not be deter- 

 mined. It is soluble in alcohol, but not in aether, and when it 

 is added to a strong aqueous solution, the aether precipitates 

 the salt in the state of a black powder; solution of potash 

 dissolves it. 



This double iodide of potassium and platina was thus ana- 

 lysed : —Twenty grains were heated until the iodine was ex- 

 pelled from the iodide of platina, and there remained metallic 

 platina mixed with iodide of potassium ; the latter was dis- 

 solved in water; the solution by evaporation left 7*75 grains 

 of iodide of potassium, and the platina weighed V75 grains, 

 consequently 7*5 grains of iodine were expelled by heat. It 

 appears therefore to be composed of 



Iodide of potassium 7*75 



platina 12-25 



20- 

 Mr. Kane observes, that " 7*5 iodine to 4*75 platinum is 

 very nearly in the ratio of l| atom of iodine to 1 atom of pla- 

 tinum, — thus proving the accuracy of the previous analyses ;" 

 and he regards the true composition of the double salt to be 

 1 atom of each iodide. The results above mentioned cer- 

 tainly prove the inaccuracy of the previous or of the present 

 analysis ; for 7*5 iodine -f 4*75 platina form a compound ex- 

 actly intermediate between a sesqui-iodide, and a prot-io- 

 dide. 



The next compound which Mr. Kane formed, lie terms 

 Iodo-platinate of hydrogen; it was formed by adding an iodide 

 of platina to a strong solution of hydriodic acid. The solu- 

 tion had a fine claret colour; by cautious evaporation small 

 grains were obtained which were soluble in water, and the 

 solution was red. From the facility with which it was de- 

 composed, Mr. Kane could not ascertain its composition. 



The last compound is called Iodo-platinate of ammonium.., 

 It was procured by adding solution of ammonia to that of the 

 above-named iodo-platinate of hydrogen. The ammonia 

 caused a black precipitate, which in a few minutes passed 



