1888.] On a Silico-organic Compound of a new Type. 39 



So far, cases were only dealt with in which silicon tetrabromide 

 combined with nitrogenised groups without loss of its halogen. The 

 next stage of the inquiry involved the investigation of certain inter- 

 actions in which the tetrabromide loses all its halogen. One of the 

 chief results obtained in that direction forms the subject of a sepa- 

 rate communication which accompanies this Report. 



III. " Preliminary Note on a Silico-organic Compound of a New 

 Type." By J. EMERSON REYNOLDS, M.D., F.R.S., Professor 

 of Chemistry, University of Dublin. Received September 



27, 1888. 



The subject of this note is a fine crystalline substance, and is the 

 first well-defined compound yet known in which we have reason 

 to believe that silicon is in direct and exclusive union with the 

 nitrogen of amidic groups. Its analysis and mode of formation lead 

 to the conclusion that it is silicotetraphenylamide, 



NHC 6 H 5 



NHC 6 H 5 



This body is produced when silicon tetrabromide (or the tetra- 

 chloride) is added to excess of aniline, diluted with three or four 

 volumes of benzene. Aniline hydrobromate (or hydrochlorate) is a 

 secondary product of interaction and separates, being insoluble in 

 benzene. If aniline be in excess throughout the operation, the whole 

 of the halogen precipitates as aniline salt, and there remains in 

 solution impure silicotetraphenylamide. If aniline be not in excess, a 

 bromo-compound is obtained analogous to Harden's rather ill- defined 

 chlorinated product. 



Distillation from a water-bath readily removes benzene from the 

 solution, and a liquid remains which solidifies after some time to a 

 yellowish mass. The latter dissolves in warm carbon disulphide 

 leaving a residue containing some thiocarbanilide, and cautious evapo- 

 ration of the solution leads to the separation of magnificent crystals of 

 the silicon compound. These form chiefly at the surface of the liquid, 

 as they are specifically lighter than the solution. 



When twice recrystallised from carbon disulphide, the substance is 

 obtained in a state of purity.* 



* A large quantity was prepared in June last, and about 50 grams of the pure 

 compound were exhibited on September llth, in Section B, during the meeting 

 of the British Association at Bath. 



