C.)ufl,i;'>irati<in of Aquoiri- aud (luiuuniue Cobalt CouipL-xes. 5 



[CoCUHjO)2(NHa' SO,H,0 (If, tlie isoiiior of the above iii.ligo 

 bluisli salt, remains. 



Judging I'rom tlie above reactions, we can build up tlieir 

 stereochemical structures as below. As regards the configuration 

 of the dichloraquotriannnine cobaltic salt, the two chlorine atoms 

 must, as described by Y. Shibata, be coordinated in the trans- 

 position analogous to those of the diethylenediamine pi'aseo 

 cobaltic salt, in which they are in the trans-position and show 

 green coloin*. Tlie process of formation will be as follows : 



yi\ 



NH, 



NO, 



HCl 



(Green) 



1 



Ci > 



Ho SO4 

 HCl 



N'H, 



(Green) 



SO4H 



* Two isomers of [Co Cl (H-P« (NH3)3] SO/"'' can be derived from 

 [Co CI, H,.0 (NHgjg] SO,H. The indigo blue coloured one (which is 

 easil}^ obtained by the action of water upon [Co CL, HjO (NHsl^JSO^H 

 and l>y adding an equal volume of alcohol to it) lias the following 



configuration 



H,0 



XH, 



NH, 



SO4H 



HoO 

 Alcoliol 



H.,0 



NH. 



SOa 



NH3 



(Indigo blue) 



This reaction is analogons to that of the production of the 

 chloroxalatotriammine col)altic salt, [Co CI CA (NHg).,]/'^ from the 

 dichrochloride. As to the configuration of tliis salt, only one form 

 can lie tleduced theoretically, as the following equation shows : 



(1) Werner: Ibid. 



(-1 



(o) Werner and Miolati : Zeit, physik. Cheui., 12, 35 1893. 



