692 PROCEEDINGS OF THE AMERICAN ACADEMY. 



with a pressure of 20 mm. and leaving a solid residue mainly sodium 

 chloride in the flask, a last fraction of 4.5 grams rich in pyrosulphuryl 

 chloride was obtained, as shown by its analysis (23) and behavior with 

 water. In the third case 197 grams of a liquid prepared just like the 

 144 grams above, and not previously distilled, were mixed with the 

 116 grams of phosphorus pentoxide and distilled at low pressure; only 

 38 grams could be collected, in three fractions, with the bath sur- 

 rounding the flask at 220°. On attempting to heat with the free 

 flame, because the distillate came at the rate of a drop per minute, 

 the flask exploded. These fractions were tested as to their melting- 

 point; they all solidified readily in large crystals, radiating from one 

 point, exactly as pyrosulphuryl chloride does; the first and second 

 melted at near —40°, the third near —50°; pyrosulphuryl chloride 

 melts at —37°; one of the fractions was tested for silica and contained 

 none. It would seem as if by distilling from any solid, so that a high 

 temperature is required, the silicon body is destroyed, while the more 

 resisting pyrosulphur\'l chloride can be collected. 



That no chlorsulphonic acid was present in our original distillate 

 was proved by an experiment performed in our first extended study 

 and already recorded. See page 584. 



In an attempt to obtain the ethyl ester of the silicon containing 

 body,^^ the material diluted by carbon tetrachloride was treated with 

 alcohol and after distilling off the sohent there remained in the boiling 

 flask a semi-solid mass which was silica and ethyl sulphuric acid. 

 The experiment was repeated several times, always with the same 

 result. That the ethyl ester of silicon oxychloride was not obtained 

 does not show the absence of silicon oxychloride, for such an ester would 

 hardly be stable in presence of ethyl sulphuric acid and other products 

 of water on pyrosulphuryl chloride. 



An examination of the table of complete analyses shows that differ- 

 ent specimens of the distillate contain the pyrosulphuryl chloride and 

 silicon oxychloride in different proportions, three of them show per- 

 centages approaching those required if the two substances are present 



in molecular proportions. 



s 



Calculated for S0O5CI2 + Si.OCle 12 .82% 



(2) 14.63 



(19) 15.14 



(1) 16.9 



19 Friedol and Ladcnburg prepared the ethyl ester of siUcon ox3^chloride 

 (C2n.06OSi2; reference 5. Compare Friedel and Crafts, Ann. Chim. phvs. 9, 12 

 (1886); Ladenburg, Lieb. Ann., 173, 144 (1874). 



