Configuration of A(|Uotri- and diauimine Col>alt Complexes. 



19 



H.O 



CI. + H.O 



NH. 



H.,0^ 



,NH, 



H,0 



NH:, 



NH, 



CI3 



The fact that the two water molecules of [Co(H20)2(NH3)4] CI, 

 coordinate in tlie cis-position can easily be recognized from the 

 absorption curve, which is very similar to that of the second class, 

 and also by the process of formation as follows : 



NH, 



CIb 



When Co ^'j ]^[ Co 01. 



CI (1) r. 

 Cl(6; 



CI is kept overnight in aqueous solu- 

 tion, its colour changes to carmine red and then it shows the same 

 absorption curve as that of the cis-diaquodiethylenediamine 



cobaltic chloride, Co j^-^ ^^^ eii^ CI.. This will be verified below. 



At first its two chlorine atoms are replaced by water, 

 producing the trans-diaquodiethylenediamine cobaltic chloride, 



r— TT O (1) ~1 



^'°h!o(6)^"^ CL. and then it is converted into the more stable 



r tt'o (i^ n 



cis-salt, i.e. p'*' h"^oi2 ^■■"■-' ^■^•' tlius : 



CI3 — ^ 



Molecular 

 conver- 

 sion 



Cls 



As to the complex salts of the second class, discussions follow 

 quite in the same way as in the case of the first class. Werner 



