THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



APRIL 1868, 



XXVIII. On certain Cobaltamines. 

 By Edmund J. Mills, D.Sc, F.C.S* 



HAVING had occasion in the course of my work to prepare 

 cobaltic hexammoniotrichloride in considerable quantity, 

 I have been led to perform some experiments with that substance 

 and the two pentammoniotrichlorides. The results, I believe, are 

 not without sufficient interest to be recorded in this place. 



I. Cobaltic Hexammoniotrichloride. 



Any one who has employed Gibbs's process for the separation 

 of the metals which are associated in platinum ore must have re- 

 cognized the extreme value of this compound as a reagent, and 

 the great importance of being able to prepare it with certainty 

 on the large scale. The literature of the subject, unfortunately, 

 supplied only the converse of these two conditions ; but the ge- 

 neral nature of the reaction whereby the body is usually formed 

 could be perceived without difficulty. When an ammoniacal 

 solution of cobaltic chloride is mixed with sal-ammoniac and ex- 

 posed to air, the first expenditure of chemical force with which 

 we are here concerned is devoted to the formation of the «-pent- 

 ammoniotrichloride (roseochloride) ; on further effort, the |3- 

 pentammoniotrichloride (purpureochloride) is produced; and, 

 lastly, the appearance of the hexammoniotrichloride represents the 



* Communicated by the Author. 



Phil. Mag. S. 4. Vol. 35. No. 237. April 1868. S 



