Chemistry. — "On the Ekctrochevücal Behaviour of Metals". By 

 Prof. A. Smits. (Communicated b}- Pr-of. Zkkman). 



(Communicated in llie meeting of March 23, 1918). 

 1. Introduction. 



By application of the considerations on which the theory of 

 allotropy is based to the internal state of the metals and to their 

 ciiemical as well as to their electromotive behaviour, we ai-e enabled 

 to consider all the metals, also those which serve as so-called unat- 

 tackable electrodes, from the same j)oint of view. 



These considerations rest on the more than probable assumption 

 that every metal contains metal atoms, one or more kinds of metal 

 ions, and electrons, which can be in equilibrium under definite 

 circumstances. When a metal is immersed in an electrolyte, then in 

 agreement with Nf.knst's views of the phenomenon of solution, the 

 heterogeneous equilibrium between the metal and the boundary layer 

 will be established with so great velocity, that it may be said that 

 this equilibi'ium always exists. 



When we, therefore, restrict ourselves to the simple case that the 

 metal consists of metal atoms, r-valent ions, and electrons, we may 

 say, that when this metal is immersed in an electrolyte the following 

 heterogeneous equilibria will at once set in. 



Ms M^- Y&, 



it it it 



Mi^ Mc- v6l 



Whether the homogeneous equilibi-ium will also exist in the two 

 coexisting phases between the metal atoms, metal ions, and the 

 electrons, depends on different circumstances. Whereas it seems that 

 a metal in perfectly dry condition can assume internal equilibrium 

 as a rule only at comparatively high temperature, this often takes 

 place very quickly when in contact with an electrolyte, but it may 

 also occur that the metal gets in equilibrium very slowly, or not at 

 all, under these circumstances at the ordinary temperature. 



The velocity with which a metal assumes internal equilibrium 

 under definite circumstances is undoubtedly one of the most charac- 

 teristic pi'operties of the metal. 



