24 PROCEEDINGS OP THE AMERICAN ACADEMY 



SiF 6 



To determine the proportions in which the substances act on each 

 other when water is added to the trianiline disilicotetrafluoride, we 

 have studied the reaction quantitatively with the following results. 



1.3092 grm. of the substance were dissolved in water, and the silicic 

 acid precipitated filtered out, ignited, and weighed, giving 0.1200 grm. 

 of silicic dioxide. To the filtrate was added potassic chloride, and the 

 potassic fluosilicate formed was dried at 100° and weighed, giving 

 0.7370 grm. 



These numbers agree best with the following reaction : — 



4 (C 6 H 5 NH 2 ) 8 (SiF 4 ) 2 + 6 H 2 = 



5 (C 6 H 5 NH 3 ) 2 SiF 6 + 2 C G H 5 NH 3 F -f 3 SiO, * 



as is shown by comparing the amounts of the products which would 

 be obtained from 100 grm. of trianiline disilicotetrafluoride according 

 to it, and those which were actually obtained in tbe experiment just 

 described. 



Two attempts were made also to determine the amount of ani- 

 line fluoride formed (both by titration and by conversion into calcic 

 fluoride) ; but although these experiments proved the presence of a 

 fluoride, they gave results which did not agree with each otlier or with 

 the theory, the reason being without doubt that a portion of the aniline 

 fluoride was converted into fluosilicate during the filtrations, which we 

 had to carry on in a glass funnel. 



The action of ammonia gas upon the trianiline disilicotetrafluoride 

 was studied carefully, since we hoped that it might throw light on the 

 constitution of this substance, and also that the corresponding ammonia 

 compound (NH 3 ) 3 (SiF 4 ) 2 might be formed. Neither of these hopes 

 has been realized, however, for upon passing ammonia gas over the 

 trianiline disilicotetrafluoride the compound was decomposed with a 

 strong evolution of heat, aniline was set free, and the product was the 



* As a matter of fact, it was one of the silicic acids which was precipitated ; 

 but as we do not know which one it was, we prefer to write it as silicic dioxide. 



