f)4() PROF. LETTS AND MR R. F. BLAKE ON 



iii the crystalline state on warming its cold solution, as it is only soluble to the extent 

 of less than i per cent, in a boiling solution. 



Accordingly we oxidised a considerable quantity of the primary phosphine — dissolved 

 the product in water and neutralised the solution with baryta, when a white flocculent 

 precipitate was thrown down, which readily dissolved in acids, and gave a strong 

 phosphoric acid reaction with molybdate of ammonia. There can be no doubt that it 

 was phosphate of barium. The solution filtered from it was boiled to small volume, 

 and gave a crystalline precipitate, which was purified by solution in cold water and 

 reprecipitating by boiling. It had the appearance and properties of benzyl phosphinate 

 of barium, and was proved by analysis to be that substance. 



Analysis. 



0-6367 lost at 110° C. 00630 H 2 = 989 percent. 



06367 gave 0-4296 BaS0 4 = 0-25259 Ba- 39-67 





Obtained. 



Calculated for C 7 H 7 P0 3 Ba,2H„0 



Water, 



9-89 



1049 



Barium, 



39-67 



39-94 



The concentrated mother-liquors from this salt were syrupy and had a slight odour 



of the primary phosphine. After some time they became granular from the separation of 



a crystalline salt. The semisolid mass was dried for some time in a desiccator, then 



washed with alcohol (in which it was somewhat soluble), and dried in vacuo. A quantity 



of the salt thus purified was dried at 110° and analysed. 



Analysis. 



1098 gave 0-5603 BaS0 4 = 032944 Ba = 3000 per ceut. 



Obtained. Calculated for (C 7 H 7 HP0 2 ) 2 Bu 



Barium, . . . 3000 3064 



In another experiment, the nature of the products of oxidation of the phosphine was 

 proved in a similar manner, with this difference, that after separating the phosphate and 

 phosphinate of barium, the remaining phosphinite was decomposed by sulphuric acid, 

 and the liberated phosphinous acid extracted with ether. The ethereal extract left on 

 evaporation a very viscous colourless liquid, which refused to crystallise. It was proved 

 to be the phosphinous acid by the production of a number of salts which were analysed, 

 and are described on pp. 610-611. 



In a third experiment on the oxidation of the primary phosphine, the product was 

 treated in a totally different manner, but with the same results. 



In this experiment the oxidised product was dissolved in water as before, the solution 

 boiled and acetate of zinc added. At first a precipitate was thrown down, which redissolved 

 as fast as it was formed, but presently on adding more of the zinc salt a permanent 

 precipitate was produced, which became pasty on boiling. It was filtered off, 

 and the solution concertrated, when a totally different salt was thrown down. 

 Analysis proved the first of these salts to be the phosphinate of zinc, the second the 

 phosphinite. 



