378 SIR WILLIAM CROOKES ON SCANDIUM. 



percentages of scandium ranging near to 23 '5, with a deviation of two- or three- 

 tenths of a unit one side or the other. The nearest basic salt which contains such an 

 amount of scandium has the composition 



fCH(OH)COO x CH(OH)COO-Sc : 



5l | >ScOH+ | 



[ CH(OH)000 CH(OH)COO-Sc : O 



and contains 23'49 per cent, of scandium. 



SCANDIUM /3-Di BROMOPROPIONATE, 

 (CH 2 BrCHBrCOO) 3 Sc+(CH s BrCHBrCOO) 3 ScOH. 



1 have not prepared either the normal or the basic dibromopropionate in a pure 

 state, but I have obtained a salt corresponding to equimolecular proportions of the 

 two salts, having the above composition. The acid was dissolved in water and exactly 

 neutralised with dilute ammonia. To the warm solution was added dilute scandium 

 nitrate until no more precipitate came down on the addition of either reagent to the 

 filtered solution. Scandium dibromopropionate is almost insoluble in hot or cold 

 water and, when dried over sulphuric acid in a desiccator, is a white amorphous 

 powder, so easily electrified that it requires great care in powdering and moving it 

 from one vessel to another or it flies out of the mortar or watch-glasses. 



Analysis. 



8'1 17 gr. of scandium dibromopropionate, dried at 110, yielded on ignition 0'845 gr. 

 of scandia, = 0'5598 gr. of scandium. 



Theory. Experiment. 



Sc 2 88-20 7-00 6'90 



C 15 H 16 H Br lrt 1171-33 93-00 93'10 



1259-53 100-00 lOO'OO 



The filtrate and washings from the precipitated salt were concentrated and pre- 

 cipitated with ammonia. The precipitate was dissolved in nitric acid and examined 

 in the spectrograph, whilst a corresponding test was applied to the scandia from the 

 pure analysed salt. On comparing the two spectrograms, nothing but scandium lines 

 could be detected on that of the scandia from the dibromopropionate, while on that of 

 the earth from the filtrate, yttrium could be detected in minute quantity and ytterbium 

 in larger quantities. 



