SIR WILLIAM CROOKES ON SCANDIUM. 37 



Analysis. 



12713 grs. of scandium succinate heated for ten hours to 180 lost 0'822 gr. of 

 water, and when ignited to full redness it left 6'089 grs. of scandia, = 3'943l 

 grs. of scandium. 



Theory. Experiment. 



31-02 

 62-51 



6-47 

 290-280 100-00 100-00 



SCANDIUM PICRATE, 

 { C rt H 2 (NO.),0 } 2 ScOH, 1 4H 2 0. 



The hydroxide dissolves readily in warm solution of picric acid and separates in 

 groups of long needle-shaped crystals of a rich yellow colour. When rapidly crystal- 

 lised from a strong solution, the crystals form confused feathery masses, which on 

 pouring off the mother-liquor turn to a felt-like mass difficult to drain. 100 parts of 

 water at 20 dissolve 0'95 part of scandium picrate. At 9 the same quantity of 

 water dissolves 0"37 part. Dried hy exposure to cold dry air the crystals have the 

 composition shown above. 



The picrate cannot be detonated when wrapped in tin-foil and struck on an anvil 

 with a heavy hammer. Heated in a dry test-tube it darkens, gives a slight 

 sublimate, fuses, and at a little higher temperature faintly explodes, leaving a black 

 flocculent residue, which burns off to pure white scandia at a red heat. 



The explosion, although not violent, is sufficient to blow some of the products out 

 of the crucible. The scandia therefore was estimated by precipitating the hot solution 

 with ammonia in considerable excess and well boiling the liquid before filtering. 

 Unless this precaution is taken some of the picrate precipitates as such, and slight 

 explosions occur when the precipitate is burnt. 



Analysis. 



(1) 27-497 grs. of picrate, dried at 100, gave off 5'906 grs. of water. 



(2) 27-497 grs. yielded 2'422 grs. of scandia, = T569 grs. of scandium. 



