The Coagulation of Arsenious Sulphide Sol by Cobaltic Complexes 



18 



. [CoNH3),HO,Cl]SO, + H,0 ^ rCo(NH3),(H,0)2l ^^ 

 [Co(NH3)4R,OCl]Cl, + H,0 ^ [Co(NH,),(H,0)2]Cl3 



(D) [Co(NH,)5Cl]X„ [Co(NH,X,(ILO),CL] SO,H, 



[Co(HN3)3(H,0)2Cl]SO, and [Co(NH,)3H,OCy Ci 



In the previous papei" [loc. cit.] the author discussed the 

 equihbriam of the aqueous solution of some cobaltammines and 

 showed that a comphcated equihbrium results. It was also confirm- 

 ed by coagulation experiments. Freundlich [loc. cit.] expressed 

 the same opinion regarding the salt [Co(NH3)5Cl]Clo. If in these 

 salts the substitution occurs completely as follows : 



[Co(NH3)6Cl)X, + H.,0 -^ [co(NH3),H,ü] gf 



[Co(NH3)o(H,OXXySO,H + 2H,0-^ [co(NH,X,(H,0)4"] g J:j g- 



[Co(NH3\(H,0),Cl]SO, + H,0 ^ [Co(NH3)3(H,0)3] ^^^ 

 [Co(NH3)3H,0 CL,] CI + ILO -^ [Co(NH,)3(H,0)3] CI3 



the limitinti; concentrations of these salts will have a value near 



about 



15000 



since the resulting: salts are all trivalent. But the 



experiments show that the reactions as indicated above are not 

 complete. [Co(NIÎ3)5Cl]CL gave ....^.. in a solution which stood 



6000 



I 



for over a night. [Co(NH3),,(H,0)oCl]SO.,H gave ^^^^^^ in a fresh 



solution and gave -^7777^ after three hours and there was no change 

 '^ /500 ^ 



up to the next day. It shows that the following successive 

 reactions occur: 



(1) [Co(NH3),(H,0),CL] SO,H + H,0 -^ [Co(NH3)2(H,0)3Cl] f^^^ 



(2)' [co(NH3),(H,0)3Cl] f^^^^+ tLO -: [co(NH3),(H,ü),] f^-^ 



[CD(NH3)3fH2 0)2Cl]S04 was ratlier stable in aqueous solution 



