Prof. Bunsen 07i Cacodyl Compounds containing Platinum. 397 



in ammonia. With bromide of potassium, a compound cry- 

 stallizing in long silky needles is formed. Cyanide of potas- 

 sium gives a yellowish white precipitate. By nitrate of silver, 

 the chloride of silver is thrown down, without destroying the 

 neutrality of the solution. 



The elementary analysis of the chloride of cacoplatyl, dried 

 at 110° C, was made by means of oxide of copper in a com- 

 bustion tube, the free space left in the tube being filled with 

 turnings of copper*. In a second analysis, chromate of lead 

 was used; the results were the same: — 



1. 2. 



Substance 1-44.0 1-0194. 



Carbonic acid . . 0494 0-3480 



Water 0-356 0-2475 



The chlorine was estimated by heating the compound to red- 

 ness with caustic lime. 1-0873 gramme of substance gave 

 0-580 chloride of silver, or 0-0225 silver; by direct precipi- 

 tation from the solution by nitrate of silver, from 0'987 of sub- 

 stance only 0-353 chloride of silver, or 0-1405 silver was ob- 

 tained. The estimation of the platinum and arsenic is attended 

 with some difficulty, from the circumstance that chloride of 

 cacoplatyl is not perfectly oxidized by nitric acid. 0-850 

 gramme was therefore heated in a combustion tube, with a 

 mixture of 1 part of carbonate of soda and 3 parts of chlorate 

 of potash. The contents of the tube, after digestion with 

 water, left a quantity of arseniuret of platinum. The solu- 

 tion, which was coloured yellow by a little of the double chlo- 

 ride of platinum and potassium, was thrown on a filter, and 

 the arsenic containing platinum again collected. This last 

 was dissolved in aqua regia, and some silicic acid derived from 

 the combustion tube separated. The fluid, freed from silicic 

 acid, and evaporated to dryness, was again dissolved in weak 

 alcohol, and gave 0-752 gramme chloride of platinum and 

 potassium. Besides this, 0-018 platinum was obtained by 

 heating a quantity of sulphuret, formed by transmitting through 

 the solution a stream of sulphuretted hydrogen. The fluid, 

 when filtered, was made use of ibr obtaining the quantity of 

 arsenic; it was freed from alcohol by boiling, deoxidized by 

 suli)hurous acid, and precipitated by sulphuretted hydrogen. 

 It gave 0-458 of sulphuret of arsenic, from which, by oxidation 

 with nitric acid, 1-254 of sulphate of barytes was obtained. 



• This precaution is necessary, lest some chloride of copper be carried 

 into the chloride of calcium tube with the watery vajiour; when metallic 

 copper is present, a basic chloride of copper is formed, wiiich is not 

 volatile. 



