CARRIERS IN ELECTROLYTIC SOLUTIONS 211 



1 23 4 567 



Chloride of Platini- Platinimpno- Platini- Cossa's Potassium 



Drechsel's Unknown diammine diammine diammine second platinum 

 base chloride chloride chloride salt chloride 



Those elements or groups appearing with platinum within the brackets 

 are contained in the nucleus, while those without the brackets 

 carry charges and are capable of ionization. The co-ordination number 

 of platinum in the nucleus is 6. The charge on the nucleus is therefore 

 given by the equation q = 4 6 + n, where n is the number of ammonia 

 molecules in the complex. In the first compound [Pt(NH 3 ) 6 ]Cl n = 6 

 and q = + 4. This compound therefore ionizes according to the equa- 

 tion: [Pt(NH 3 ) 6 ]Cl 4 = [Pt(NH 3 ) 6 ] ++ " + 4CK On the other hand, in 

 the compound [PtCl 6 ]K 2 , n = Q and q = 2. This compound, there- 

 fore, ionizes according to the equation: [PtCl 6 ]K 2 = PtCl 6 ~ + 2K+. 

 The manner in which the ionization takes place in the other compounds 

 may obviously be derived from the equation given. If Werner's theory 

 is correct, then, when the various compounds are dissolved in water, the 

 conductance of the resulting solutions should vary in correspondence with 

 the number of changes involved in the ionization reaction. At low con- 

 centrations, the conductance of the first compound should lie in the 

 neighborhood of 500; that of the third compound, in the neighborhood of 

 200; that of the fourth, in the neighborhood of 100; while that of the 

 fifth should be zero. On the other hand, that of the sixth should lie in 

 the neighborhood of 100 and that of the seventh in the neighborhood of 

 200. In solutions of these last two compounds, the platinum complex 

 should appear as anion. This consequence of Werner's theory has been 

 confirmed by experiment. The conductance of the first, third, fourth, 

 fifth, sixth and seventh compounds at and at a dilution of 1000 liters 

 are respectively: 522.9, 228, 96.75, 0, 108.5, and 256. 



The conductance of the fifth compound is actually not quite zero, 

 since in solution compounds of this type are not entirely stable and reac- 

 tion takes place with the water, wherein molecules of water enter the 

 nucleus and thus produce a charged complex, the water functioning in a 

 manner similar to that of ammonia. However, in many cases values of 

 A less than unity have been obtained, and it has been shown that the 

 conductance is a function of the time and that, moreover, the reaction is 

 catalyzed at the electrode surfaces. 16 * 



There can be no doubt but that the ionization of the complex metal- 

 ammonia and other similar salts depends upon the combination of am- 



" Werner and Herty, Ztachr. f. phya. Chem. 38 f 331 (1901). 



