BENZYL PHOSPHINES AND THEIR DERIVATIVES. 557 



with compounds of what was known to be oxide of tribenzyl phosphine. We may 

 add that many of the compounds are unstable, and their composition frequently varies 

 with the method employed in their preparation. In many cases indeed it appears to be 

 almost impossible to obtain them pure. 



Bromide. — This compound, which is highly characteristic, was obtained by adding 

 bromine to a solution of the body in glacial acetic acid. It usually crystallises in 

 yellow needles, which under the microscope appear to consist of aggregations of minute 

 rhombohedra. It is unstable, and gives off bromine when boiled with water or glacial 

 acetic acid, and its composition varies considerably (see p. 625). 







Prepared from 



A 





Bromine, . 

 Carbon, 

 Hydrogen, . 



Hofmann's Dibenzyl Phospli 



Obtained. 

 26-7* 

 565 + 

 5-3 J 



:ine. Oxide oi 

 Calculated for 



A 



: Tribenzyl Phosphine. 



Obtained. 

 28-4 f 

 569 

 4-9 



Bromine, 

 Carbon, 

 Hydrogen, . 



{(C 7 H 7 ) 2 HP} 2 ,Br 2 

 27-2 

 571 

 51 



7(C 7 H r ) 3 PO,5Br„ 

 2631 

 5800 



4-88 



5(C 7 H 7 ) 3 PO,4Br, 

 28-5 

 56-3 



4-7 



Iodide. — Prepared like the bromide. It crystallises in minute red crystals of the 

 same colour as ferricyanide of potassium. 



Calculated for 



Obtained. , * 



{(C 7 H 7 ) 2 HPM, 7(C 7 H 7 ) 3 PO,5L, 5(C 7 H 7 ) 3 PO,4l 2 

 Iodine, . . 3686 3724 36-18 38*84 



Chloride. — Obtained by passing chlorine into a solution of the body dissolved to 

 saturation in warm acetic acid. It crystallises when the solution cools in pale yellow 

 crystals, much like pentachloride of phosphorus in appearance. The compound is most 

 unstable, and loses chlorine rapidly in vacuo, and probably also when air-dried. 



Calculated for 



Obtained. , A * 



{(C 7 H 7 ),HP} 0) C1 2 7(C 7 H 7 ) 3 PO,5Cl 2 



Chlorine, . . 1200 1423 1468 



Hydriodate. — Obtained by saturating a solution of the body in glacial acetic acid 

 with hydriodic acid gas, and separated as the solution cooled in colourless crystals. 



Calculated for 

 Obtained. 



2(C 7 H 7 ) 2 PH,HI 3(C 7 H 7 ) 3 PO,2HI 

 Iodine, . . {21-5} 22 ' 8 21 ' 05 



* Mean of ten determinations of different preparations of the compound. The extremes were 25 - 9 to 27'2. 



t An old analysis by one of us and N. Collie, these Transactions, xxx. part 1. + Mean of three determinations. 



