32 W. G. Mixter — Polymerization of Oxides. 



E + O + H 2 0* E + = EO EO + H 2 



(amor.) 



Zn 82-7 80-3f 2-4 Cal. 



Cd 65-7 §§57 \ 8-7 



Mil. 94-8 90-8§ 4-0 



Fe 68-3 §§64-3j 4-0 



Co 63-4 50-5 12-9 



*Thomsen. f De Forcrand, loc. cit. % This Journal, xxxvi, 55, 1913. 

 §§Ibid., xxx, 193, 1910. § LeChatelier, C. E., cxxii, 81. 



Thomsen derived the heat of formation of the hydroxide of 

 a heavy metal from the heat effect when the metal is dissolved in 

 a dilute acid and the heat of neutralization of the hydroxide of 

 the metal by the acid. Hence the hydroxide may be regarded 

 as formed by the union of water with un polymerized molecules 

 of oxide. The derived values for ZnO -j- H 2 = 2*4, MnO + 

 H 2 = 4-0, FeO + H 2 = 4-0 may be low since the heats of 

 formation of the oxides may include a small heat effect due to 

 polymerization at high temperatures. The value Cd + O = 57 

 is regarded only as an approximation and hence the same is 

 said of CdO + H 2 = 8-7. The value CoO 4- H 2 = 12-9 is 

 undoubtedly too large. There is an error in the data from 

 which it is derived. 



