258 Dr. E. J. Mills on certain Cobaltamines. 



for forty-eight hours at 100°. The precipitate, dried as before, 

 weighed approximately 0*5770 grm. \ 0*2663 grm. of it gave 

 00137 grm. water, 0150 grm. silica, 0*4467 grm. cobaltic sul- 

 phate. The composition of the precipitate was — 



Found. 

 ( -V x 3Co 2 3 .CoO. 



Cobalt . . 64-521/ 72*31 72*41 



Oxygen . . 24*71J \27*69 27*59 



Silica . . . 5*63 



Water . . . 5*14 . 



100*00 100*00 100-00 



grm. 

 The amount of cobalt due from the ammoniochloride is 0*1931 



chloride is . . 0*1935 



Total . . . 0*3866 

 Jy found in the weighed precipitate was 0*3723 



The nitrate contained 00082 grm. free ammonia ; it gave no 

 precipitate with amnionic polysulphide, — a result which is quan- 

 titatively corroborated by the above numbers. As in the former 

 case, there has been considerable oxidizing action from external 

 sources, viz. the air in the closed vessel and the hot air in the 

 desiccating bath ; yet this has not proceeded to such an extent 

 as to mask entirely the real nature of the process. Although 

 the oxide Co 4 O 5 , as thus generated, is evidently more prone to 

 oxidation than as at first obtained, yet the oxide actually analyzed 

 still shares with it the property of deriving at the same time 

 from cobaltic dichloride and terchloride. 



Hex ammoniochloride. — The conditions and results of neutrality 

 are 

 3CoCl 2 + 2(CoCl 3 .6NH 3 ) + (6 + 7i)H 2 = Co 5 6 .7iH 2 01 , A . 



-fl2(NH 3 .HCl). . . ]W 



0*40275 grm. hexammoniochloride, 0*294 75 grm. cobaltic chlo- 

 ride, and 75 cubic centims. of water were digested for fifty hours 

 at 90°, in sealed tubes, without undergoing much alteration ; but 

 on further heating for forty-seven hours at 110°-120°, complete 

 decomposition ensued. The precipitate, dried at 100°, weighed 

 approximately 0*3602 grm. ; 0*3335 grm. of it gave 0*0161 grm. 

 water, 0*0463 grm. silica, and 05139 grm. cobaltic sulphate. 

 The composition of the precipitate was — 



Found. 



( ^ N 2Co 2 O 3 . CoO = Co 5 6 . 0. 



Cobalt . . 59*27\f 72*91 72*82 



Oxygen . . 22-02/ \27*09 27*18 



Silica. . . 13*88 



Water . . 4*83 



100*00 10000 100*00 



