ChloriodiJc of Platinum. 259 



violet vapor of iodine are evolved, leaving the platinum in a spongy 

 form like that ohtained by heating the ammonia-muriate of platinum. 

 Some of the chloriodide of platinum was decomposed by heat. 

 The loss of chlorine and iodine in the successive experiments was, 

 1. - - - - - 67.20 per cent. 



2. 70.50 " " 



3. 67.22 " " 



4. 68.50 " " 



The variation in the amount of loss by vaporization, is due to the 

 vapor carrying ofFsome of the finely divided platinum, when the vap- 

 orization was rapid. On dissolving the iodine and chloride of iodine, 

 which were condensed in the cool part of the tube in which tlie ex- 

 periment No. 2 was performed, by solution of potassa, a residue of 

 platinum was observed. 



Synthesis of Chloriodide of Platinum. 



Ten grammes of spongy platinum, recently prepared from the 

 chloride manufactured by RobiquetandBoyeau of Paris, were treated 

 with dilute nitromuriatic acid, that the iridium, palladium, &c. might 

 remain undissolved. A black powder remained, and the solution be- 

 ing allowed to stand some days, that which had been held in suspen- 

 sion was deposited. It proved to be iridium. It was separated by 

 careful decantation and washing, the washings after being allowed 

 to stand on the powder a day each, were drawn off by a glass syringe 

 and added to the solution of muriate of platinum. The iridium 

 weighed 0.095 grammes. Tlie solution of muriate of platinum was 

 evaporated, so that when cold it was of the consistence of honey. 

 Lest there should be some free nitric acid, which could not be sepa- 

 rated by heat, without decomposing the muriate of platinum, some 

 muriatic acid was added, to decompose any nitric acid that might be 

 contained in the solution. The solution was then evaporated until 

 it solidified in cooling. The solid muriate, or hydrated bi-chloride 

 of platinum, was crystallized in long acicular crystals, radiating from 

 the center to the circumference of the capsule, and weighed 24.64 

 grammes. 



This muriate or hydrated bi-chloride of platinum was then dissol- 

 ved in water, and hydriodic acid in excess added. The solution was 

 evaporated to dryness. Hydrochloric acid passed over until the mass 

 was dry, and then yellowish fumes of chloride of iodine in small 

 quantity, until the heat was raised to near 300° F, when the fumes 

 ceased to be evolved. 



