ê8Ö 



of the theory of allotropy, as it necessarily led to the conclusion 

 tiiat the stable red or violet modification is really complex, and 

 consists at least of two components, which greatly differ in volatility. 



As the denomination red phosphorus is universally known, we 

 will also apply this term to the stable modification, though, as was 

 yaid before, this modification is violet in coaiser crystalline state. 



The adjoined figure represents the vapour pressure line, as it has 

 been found by us after laborious study, and the table gives the 

 vapour pressures at different temperatures, as they can be read from the 

 vapour pressure line. In a following communication this investigation 

 will be treated more fully. 



Amsterdam, Sept. 25, 1914. Anorg. Chem,. Laboratory 



of the University. 



Chemistry. — ''The application of the theory of allotropy to electro- 

 motive equilibria:' III. By Prof. A. Smits and Dr. A. H. W. 

 Aten. (Commujiicated by Prof. J. D. van der Waals). 

 (Communicated in the meeting of Sept. 26, 1914). 

 Introduction. 



The application of the theory of allotropy to metals necessarily 

 led to the assumption that every metal that exhibits the phenomenon 

 of phase allotropy, must contain different kinds of ions. As -was 

 already mentioned before, these kinds of ions can 1. differ in com- 

 position, the electric charge per atom being the same; 2. differ in 

 valence with the same composition, and 3. differ in composition and 

 charge per atom. 



On extension of the said theory to the electromotive equilibria it 

 was now demonstrated 1. that the unary electromotive equilibrium 

 finds its place in a A,t' figure of a pseudo system, 2. what can be the 

 relation between the unary and the pseudo-binary system, and 3. what 

 phenomena will have to appear when in case of electrolytic solution 

 resp. separation of metals the internal equilibrium is noticeably 

 disturbed. The phenomena of anodic and cathodic polarisation appeared 

 by this in a new light and the passivity of metals revealed itself as 

 a disturbance of the internal equilibrium in the metal surface in the 

 direction of the noblest kind of ions^), which view seemed already 

 to be confirmed by a preliminary investigation *). 



Thus we had arrived at the region of the passivity of metals, and 



') These Proc. XVI p. 699. 

 2} These Proc. XVII p. 37. 



