122 ACTION OF AQUEOUS AMMONIA ON 



Hg CI, + 2NH3 = CU Hg (NH3), 



Cl.Hg(NH3),-;lCl-Hg-NH, + NH,Cl 



J. G. F. Druce" has proved that one molecule of ammonium 

 chloride is formed in the reaction, but he gives the intermediate 

 steps as follows: — 



HgCU + NH,OH = CI— Hg— NH,+HCH-H,0 



HC]+NH,0H = NH,C1+H,0. 



The best mechanism probably is that the reaction proceeds as 

 with organic chlorine derivatives: 



CI— Hg— C1 + NH3 = C1— Hg— NH^"" +C1~" 



CI— Hg— NHj-^ +NH3 = C1— Hg— NH.+NH + 

 according to the analogy 



R— C1 + NH, = R— NH3■^+C1— 

 R— NH3+ +NH3 = R— NHa + NH^-^ 

 In both these reactions, before substitution takes place,- there 

 may be some feeble addition compound formed between the 

 chlorine and the ammonia. 



The action of aqueous ammonia on mercurous chloride may 

 be summarized by the following series of equations which re- 

 present what seem to be the most probable steps in the reaction. 



Hg = HgCla:;tHg + HgCl. 



HgCla + NH3 = Cl— Hg— NH3-^ +C1— 



CI— Hg— NH3-^ +NH3 = C1— Hg— NH.+NH + 



XCl— Hg— NH, = (CI— Hg— NH,)x 



This analysis of the reaction between aqueous ammonia 

 and mercurous chloride was car/ied out as a part of a general 

 investigation into the possibility of separating isotopes chemi- 

 cally. The point of interest was that mercurous chloride gave 

 two different mercury derivatives in the reaction, namely 

 metallic mercury and infusible white precipitate. If the old 



