1876.] Specific Volumes of Liquids. 295 



volume as in phosphoryl trichloride. On the other hand, the order of the 

 divergences shown by P, As, and Sb (vide infra), would appear to indi- 

 cate that V may be pentad in this compound, whence would have the 

 volume 12-2. 



Comparison of the specific volumes of PC1 3 , AsCl 3 , and SbCl 3 : — 

 VI. Phosphorus Trichloride. 



I prepared this compound by heating purified amorphous phosphorus 

 in dry chlorine gas. The reaction is very regular, and large quantities 

 of the liquid may be thus obtained with great ease and rapidity. The 

 product was digested with ordinary phosphorus for some weeks to remove 

 the last trace of free chlorine. On distillation the liquid commenced to 

 boil at 76°* 05, and all came over below 76°-25, the most constant point 

 appearing to be at 76°-15. w=18°-2, f=26°-0. Bar. 768-2 millims. 

 Corrected and reduced boiling-point 75°- 95. Two determinations of 



specific gravity gave — 



1 1-61290 



II 1-61299 



Mean 1-61294 at 0° 



compared with water at 0° ; compared with water at 4° its specific gravity 

 is 1-61275. 



Other observers have found for the boiling-point and specific gravity 

 of phosphorus trichloride : — 



B.P. Bar. . Sp. gr. at 0° com- 



millim. pared with water at 4°. 



Pierre* 78-34 751-5 1-61616 



H. L. Buff f . . 76-0 760-0 1-61191 at 0°$ 1-61170 



Haagen§ .... 76-0 745-9 1-5774 at 20° 1-61165 



The observations with the dilatometer have led to the formula 



Y=l + 0-001 139 37* + 0-000 001 668 07* 2 

 + 0-000 000 004 012?, 



by means of which the following Table, showing the true volume of phos- 

 phorus trichloride at every 10° between 0° and 80°, has been calculated : — 



°0. 



Volume. 



Diff. 



°0. 



Volume. 



Diff. 







100000 





50 



106164 



1314 



10 



101156 



1156 



60 



107523 



1359 



20 



102349 



1193 



70 



108931 



1408 



30 



103579 



1230 



80 



110388 



1457 



40 



104850 



1271 



75-90 



1-09784 





* Loc. cit. p. 9. t Ann. der Chem. und Eharm. Suppl. vol. iv. p. 184. 

 \ Mean of 1-61253 and 1-61128, compared with water at 0°. § Loc. cit 



