510 



metals. The chloride-of-potassium compound, according to Zeise's 

 researches, contains 



C 2 H 4 Pt 2 Cl 2 ,KCl. 



The chloride-of-ammonium compound has an analogous compo- 

 sition. Zeise further observed that his platinum compound unites 

 directly with ammonia, producing a substance of the formula 



C 2 H 4 Pt 2 Cl 2 ,NH 3 . 



The correctness of these formulae Liebig, relying on certain theo- 

 retical conceptions, has called in question. The discussion which 

 followed his remarks has, however, in no way decided the constitution 

 of these compounds. 



We have undertaken to prepare and analyse some new double com- 

 pounds of this series, in order if possible to elucidate the constitution 

 of Zeise's bodies. 



We first endeavoured to establish the nature of the gas which 

 under various conditions is evolved from Zeise's compounds. For 

 this purpose we exposed the potassium-salts above mentioned to a 

 temperature of 200, and collected the gas which was evolved, over 

 bromine water. In this manner an oily liquid was obtained, which 

 was easily proved to be identical with dibromide of ethylene. The 

 formation of the gas seems to ensue according to the folio wing equation, 



C 2 H 4 Pt 2 C1 2 , KCl=Pt 2 C1 2 + KCH-C 2 H 4 . 



The formation of ethylene-gas, as well as the analysis of several 

 salts which we prepared, seems to indicate that the original formulae 

 given by Zeise are correct, and that the existence of the group 

 (C 2 H 6 ) 2 O assumed by Liebig in these substances is not supported by 

 experimental evidence. 



We have succeeded in combining ethylene-dichloride of platinum 

 (this is the name which we propose for Zeise's compounds) with 

 mono- and diatomic bases. We have also combined this substance 

 with the chlorides of the bases. 



The bodies thus obtained may be arranged in two series, comparable 

 in many respects with certain classes of compounds which proto- 

 chloride of platinum forms with organic bases. If ethylene-dichloride 

 of platinum be viewed as the chloride of a monoatomic radical thus, 



(C 2 H 4 Pt 2 Cl)Cl, 

 a very simple relation between the derivatives of this substance and 



