History of the Phosphorus Chlorides. 307 



V CI 3 PO CP Sb SCI 3 



V 2 2 C1 4 N 2 2 C1 4 



V 2 2 C1 2 N 2 2 C1 2 As 2 2 Cl 2 * Sb 2 2 Cl 2 t 



V 4 4 C1 2 



• 



The V 2 O 2 Ci 4 was also prepared by Roscoe by heating VO CI 3 

 in a sealed tube with fragments of metallic zinc to a temperature 

 above the boiling-point of mercury ; in this way the compound 

 was obtained in quantity ; and it was easily freed from a small 

 quantity of adhering VO CI 3 by heating to 130° C. in a current 

 of dry carbon dioxide. I have attempted to repeat this reaction 

 with phosphoryl trichloride. A quantity of the pure liquid was 

 sealed up together with zinc filings in a tube and heated to about 

 400°. The zinc was slowly acted upon, and a transparent glassy 

 mass was formed at the bottom of the tube. No evolution of 

 gas occurred on opening the tube. The small quantity of liquid 

 remaining was submitted to distillation ; it commenced to boil 

 at about 80°, and the thermometer gradually rose to 105°, by 

 which time the whole of the liquid had passed over. This be- 

 haviour appeared to indicate the presence of phosphorus trichlo- 

 ride, PCI 3 ; and a few drops of the liquid decomposed by water 

 yielded the reactions of phosphorous acid. The quantity was 

 too small to admit of fractional distillation, even if the perfect 

 separation of the two liquids had been practicable by this method. 

 Accordingly three portions of the distillate were weighed out 

 for determination of the chlorine, total phosphorus, and amount 

 of phosphorus yielding phosphoric acid on decomposition with 

 water. 



I. Determination of chlorine. — The weighed quantity of liquid 

 was decomposed by water in a stoppered bottle, a quantity of 

 nitric acid added, and the chlorine precipitated with silver nitrate. 



0-6032 grm. gave 1'7764 AgCl and 0-0075 Ag. 



CI found. Calc. for PO CI 3 . For PCI 3 . 



73-21 per cent. 69'36 77'43 



II. Determination of total phosphorus. — The mixed chlorides 

 were decomposed by water in the manner above described, nitric 

 acid added, and the liquid concentrated. The fluid was then 

 made strongly alkaline by ammonia, and the phosphorus preci- 

 pitated as the magnesium ammonium compound. 



1*3343 grm. gave 1*0077 magnesium pyrophosphate, or 21*09 

 per cent. P. 



III. Determination of the phosphorus existing as phosphoryl 

 chloride, yielding phosphoric acid on decomposition with water. 



* Wallace's chlorarsenic acid. f SchaefFer. 



X2 



