396 Prof. Bunsen on Cacodyl Compounds containing Platinum. 



replaced bycacodyl. The results obtained tend to throw a 

 new light on the relations in which the organic bases, or alka- 

 loids, stand towards the simple oxides of metals. 



Chloride qfCacoplatyl. 



By mixing an alcoholic solution of chloride of platinum 

 with a similar solution of chloride of cacodyl, a precipitate of 

 a reddish-brown colour is obtained, which, when washed with 

 alcohol and reduced to powder, becomes yellowish-red, and 

 is inodorous. When this powder is heated, it melts into a clear 

 yellow gummy mass, gives off hydrochloric acid and vapours 

 smelling of chloride of cacodyl, and leaves behind a gray-co- 

 loured arseniuret of platinum. Both the chlorides of pla- 

 tinum and cacodyl are indicated in this compound by reagents. 

 Should this compound be analogous to the chloride of caco- 

 dyl, its composition would be, Pt CI + Kd CI. This bod}', 

 however, could not be analysed, for it is so easily decomposed 

 as not to be of uniform composition. If the precipitate in 

 question be boiled with water, a yellowish solution is formed, 

 alcargen being generated at the same time, and the solution 

 on cooling deposits white needle-shaped crystals. This sub- 

 stance may be named chloride of cacoplatyl^ and from this 

 name the others will be derived. To obtain the chloride of 

 cacoplatyl in larger quantities and in a more easy manner, an 

 aqueous solution of chloride of platinum is boiled with chlo- 

 ride of cacodyl. The precipitate, which falls first of a brown 

 colour, is changed by boiling into a wine-yellow colour. The 

 precipitation of the chloride of cacoplatyl commences even 

 during the boiling, and by cooling still more is deposited. 

 The mother liquid contains nothing except a little alcargen 

 (or perhaps a true salt of cacodylic acid and oxide of platinum). 

 The crystals are collected on a filter, and purified by redis- 

 solving. This compound possesses the following properties : — 

 it crystallizes from a hot solution in long sharp needles, which 

 are beautifully formed, is inodorous, its taste disgustingly 

 arsenious. It is soluble in hot alcohol and water, more 

 sparingly so in these liquids cold. When heated it becomes 

 yellow, then brown, and without melting takes fire and burns 

 like tinder, giving off' vapours smelling of arsenic, and leaving 

 behind fusible arseniuret of platinum. Sulphuric acid, by 

 depriving the compound of water, turns it yellow. Hydro- 

 chloric acid has no action. In ammonia it is soluble in all 

 proportions ; by evaporating the solution, imperfect crystals 

 are formed, which are insoluble in alcohol. Iodide of potas- 

 sium produces in the solutions of chloride of cacoplatyl a 

 yellow precipitate, which dissolves of a reddish-brown colour 



