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XXXI. Analysis of some Combinations of Platina. By R 

 Kane, M.R.I.A. Professor of Chemistiy to Apothecaries' Ha, 

 Dublin*: with Observations by R. Phillips, F.R.S. &c< 



11/1 R» KANE prepared iodide of platina by adding a solu- 

 "***•"» tion of hydriodate of potash to a dilute solution of per- 

 muriate of platina, the latter being in excess ; a black preci- 

 pitate was formed, which consisted of iodide of platina mixed 

 with the double chloride of potassium and platina ; the latter 

 was dissolved by putting the precipitate into a large quantity 

 of water, and keeping it at a temperature of 200°. The insolu- 

 ble residue was iodide of platina, which when cautiously dried 

 had the following properties: its colour was dull black, rather 

 heavy, insoluble in warm water, but by long boiling in water, 

 traces of iodine were perceptible, arising from the decom- 

 position of a minute portion of the iodide. Alcohol and aether 

 did not appear to act upon it; when heated to 250° it began 

 to give out iodine copiously, and below a red heat it was to- 

 tally decomposed, leaving metallic platina. Neither sulphuric, 

 nitric, nor muriatic acid acted upon it when cold ; but a mixture 

 of the two latter dissolved it, permuriate of platina being form- 

 ed, and iodine expelled. Solution of potash dissolved the 

 iodide of platina, the colour of the solution was yellow ; when 

 saturated with nitric acid it became of a claret colour, more 

 acid rendered it colourless, and by alcohol it was resolved into 

 a mixture of metallic platina and iodine. £0feJ 



A solution of hydriodic acid dissolved the iodide of platina, 

 the solution was red : it was dissolved also by a solution of 

 hydriodate of potash, and its colour was deep claret; when the 

 iodide was put into a solution of ammonia, it became first 

 greenish, then brown, and finally of a clear Indian red; the 

 supernatant liquor was yellow, it contained excess of ammonia, 

 and by evaporation deposited minute red crystals. 



To determine the composition of the iodide it was decom- 

 posed by heat; 100 grains left 35 of platina, and consequently 

 65 of iodine were dissipated : on repeating the experiment 

 there was but a slight variation in the result. Now a com- 

 pound of 3 atoms of iodine (126 x 3) 378, and 2 atoms of pla- 

 tina (96 x2), 192 = 470, would give 66*3 of iodine, and 33*7 

 of platina per cent. It appears, therefore, that this substance 

 is a sesqui-iodide, composed of 



1 \ equivalent of iodine (126 + 63) 189 or 66*3 

 1 platina ..... 96 33*7 



j 



285 100' 



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* From the Dublin Journal of Medical and Chemical Science, for July 



1832. 

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