Mixter — Formation of the Oxides of Cobalt and Nickel. 197 



CoO (amor.) + Na,0, = Na,CoO, + 30-3^ 



Na,0 + O = Nap, + - 19-4'= 



CoO + O + Nap ^ NapoO, + ^^'V 



Co + 20 + Na„0 = Na„CoO, + 100-2= 



CoO + O + Nap = Na'poO, + 49-7'= 



Co + O = CoO (amorphous) + SQ-S-^ 



3 (Co + 20 + NaP) = SNapoO, + SOO-G^ 



CO3O, + 20 + 3Nap = 3Napo03 + 107-2« 



3Co + 40 = CO3O, + -- 193-40 



Sodium cobaltite, NaPoOj, has not been isolated, but very 

 probably is formed in the fusions where there is an excess of 

 sodium peroxide because cobaltites of other metals exist, as for 

 example BaCoO, , and MgCoO, . Whether Na^CoOj is formed 

 in the fusion or some other sodium cobaltite makes no differ- 

 ence in the heat of oxidation derived, since the same cobaltite 

 is formed in the fusions containing either cobalt or a cobalt 

 oxide. 



The heat effect of I^aP + CoO, cannot be derived from the 

 results, since the heat of formation of CoO, is not known. It 

 is, however, 7-8° or greater. Assuming that one atom of 

 oxygen combining with CoO gives the same heat effect as 

 when combining with 3CoO, we have 



Co + 20 = 50-5 + 41-9 = 92-4'= 



and Co + 20 + Nap = Nap CoO, + 100-2= 



Co + 20 r= CoO, + -. 92-4=? 



Nap = CoO = Na,0 CoO, + 7-8<=? 



Nickel. 



Two preparations of nickel were made from nickel carbonate 

 from the J. T. Baker Chemical Company by converting it into 

 oxide and then reducing with hydrogen. The preparation 

 designated as a was reduced at a bright red heat. The nickel 

 obtained was light gray and coherent. It was pulverized and 

 sifted through 1/50 inch mesh. "When burned in air it yielded 

 only a trace of water, showing it to contain too little hydrogen 

 to affect the calorimetric results. Another reduction was made 

 (5) at a temperature of approximately 510°, and when it was 

 complete the hydrogen was pumped out until the pressure fell 

 to 30""". The apparatus containing the metal was then left to 

 cool. When it was poured into a bottle oxidation took place 



