Chemical Properties of Stannic Chloride. 



487 



ing the following question: Whereas hydrochloric-acid gas, 

 alcohol, ether, aqueous hydrochloric acid, sulphuretted hy- 

 drogen and alcohol, render stannic chloride an electroly sable 

 liquid, why do not chlorine, sulphuretted hydrogen, chloro- 

 form, the various solids mentioned in Part 1., exert a similar 

 influence ? 



The answer is, that the former enter into chemical combina- 

 tion, the latter do not. To quote the concluding sentence of 

 Part I., the latter class of substances " producing no effect on 

 the chemical homogeneity of the stannic chloride, which 

 remains merely stannic chloride, are without influence on its 



electrical conductivity : " a collection of unit particles, | SnCl 4 1 , 



even where mechanically interspersed with foreign substances? 

 do not conduct. But when hydrochloric-acid gas, alcohol, 

 ether, hydrochloric-acid solution, sulphuretted hydrogen and 

 alcohol, are added, electrolytic power is developed. Here, 

 however, there is no longer chemical homogeneity. 



The stannic chloride charged with hydrochloric-acid gas 

 must contain a collection of molecules of the double chloride 

 2HC1 . SnCl 4 interspersed amongst molecules of stannic chlo- 

 ride. There is here manifestly the potentiality of a continual 

 condition of interchange between the combined and uncom- 

 bined stannic-chloride molecules ; a condition of dynamical 

 equilibrium maintained by changes of this nature : — 



<SnCl 4 | | 2HC1 



icTj I + fsnClTj — '^nClTj + IjS 



2HC1|| SnCl 4 



a (5 y a, (3 y 



The similar phenomenon is repeated under the influence of 

 absolute alcohol ; here the alcoholate SnCl 4 . 2C 2 H 5 OH is 

 formed and dissolved in the excess of alcohol. The equili- 

 brium would depend on, here, the interchange of the com- 

 bined alcohol molecules for the uncombined : — 



r ^ 



[snClTj |20 2 H 5 OHJ 



+ | SnCl 4 | -^ | SnCl 4 | + 



a j3 y a 



Similarly for the etherate SnCl 4 . 2(C 2 H 5 ) 2 : 



fsnClV |2(C 2 H 3 XPJ . + fsnOlT) "** [IbOu] + 

 a /3 y a, 



2 P2 



r 





| SnCl 4 1 1 2C 2 H 6 OH ] 



,, 





P 



7 





•\ 



1 2(C 2 H 6 ) 



P\\SnC\ | 



