SANGER-RIEGEL. — SULPHUR TRIOXIDE-SILICON CIILORIDK. 595 

 S CI SI 



26.8% 18.3% 0.2% 



The study of this soHd suggests tliat it is siHca enclosing niucli sulphur 

 trioxide and some sihcon oxychlori<le an<l pyrosulphuryl chloride. 

 This silica would have been formed by the equation, which has been 

 discussed before, 



SioOCle + 6SO3 = 2Si02 + 3S0O5CI0 



Our reasons for contending that silico-phosgene is not formed have 

 been fulh' stated in the introduction. 



SUMMARY. 



Melted sulphur trioxide and silicon tetrachloride are miscible; on 

 standing a long time or on heating 6 to 10 hours to 50° a reaction 

 takes place: 



2SiCl4 + 2SO3 = SioOCle + S2O5CI2; 



an excess of sulphur trioxide causes a further reaction : 



SioOClg + 6SO3 = Si02 + 3S2O5CI2 



The most significant result, as regards the relation of carbon and sili- 

 con, is the non-formation of silico-phosgene. 



We take pleasure in acknowledging a grant from the Cyrus M. 

 Warren Fund of Har^•a^d University, with which the expense for the 

 liquid air was met. 



Chemical Laboratory, Harvard University. 



