Dr. E. J. Mills on certain Coballamines. 247 



4*4 parts of aqueous ammonia likewise furnish, under similar 

 treatment, abundance of the hexammoniochloride. 



(4) Dieobaltic teroxide is almost wholly transformed into this 

 substance when heated in sealed tubes at 70° with large quan- 

 tities of sal-ammoniac and strong aqueous ammonia. 



(5) The same is true of the hydrous mixture of cobaltic 

 w-oxide and silica which is precipitated when cobaltic hexammo- 

 niochloride or /3-pentammoniochloride is decomposed by about 

 thirty or forty times its weight of water in sealed glass tubes at 

 70°-100° C. 



(6) Even a very weak solution of cobaltic chloride, to which 

 abundance of sal-ammoniac, strong aqueous ammonia, and solid 

 calcic oxychloride have been successively added, will give, after 

 eighteen hours' repose, a decided yellow precipitate with hydric 

 chloride. 



(7) A concentrated solution of cobaltic chloride is treated 

 with rather more ordinary aqueous ammonia (previously diluted 

 with its own volume of water) than is necessary to dissolve it ; 

 iodine or bromine is next added in small portions at a time, but 

 not so as to saturate the whole of the ammonia ; and then, if a 

 considerable bulk of a mixture of equal volumes of spirit and 

 aqueous hydric chloride be stirred in, a crystalline powder falls 

 which is very nearly pure cobaltic hexammoniochloride. 



(8) Cobaltic /3-pentammoniochloride is converted into hex- 

 ammoniochloride by digestion at 60°-70° in sealed tubes, with 

 strong aqueous ammonia (of sp. gr. 0*887 at 12°*5), either 

 in the presence or absence of sal-ammoniac. According to 

 Fremy*, mere ebullition of the chloride and aqueous ammonia 

 will suffice to effect the conversion required. I have verified 

 this statement; but the quantity of product is so excessively 

 small that the process is practically useless. That the generally 

 received equation f 



(/3) 5NH 3 .CoCl 3 + NH 3 =6NH 3 .CoCl 3 



is not true, will be apparent from the following numbers : — 



(a) 0*4255 grm. pentammoniochloride, dried at 60°-70°, and 

 digested for about eighteen hours, as above specified, yielded, on 

 extraction with dilute aqueous hydric chloride and precipitation 

 with alcohol to which much hydric chloride had been added, a 

 quantity of the hexammoniochloride which, when placed on a 



ployed ( Ann. der Chem. und Pharm. vol. cxlii. p. 50) : the action is 

 allowed to take place in vessels which are open to the air. Judging from 

 the description given by that chemist, the results are very much more sa- 

 tisfactory if the operation be performed as I have suggested, in vessels 

 which are hermetically sealed and subsequently heated. 

 * Pelouze et Fremy, Traite, 3rd edit. vol. hi. 1. p. 565. t Co=60. 



S2 



