374 SIR WILLIAM CROOKES ON SCANDIUM. 



gummy mass when evaporated to dryness. It has a strong mousy odour. The 

 ammoniacal solution also dries to a clear glassy mass, entirely soluble in water. 



Analysis. 



(1) 10-131 gr. of scandium malate dried in a vacuum desiccator lost 0'852 gr. of 



water after being kept at 110 for twelve hours. 



The same 10'131 gr. of scandium malate, after ignition, left 3'324 gr. of 

 scandia, = 2'152 gr. of scandium. 



(2) 8-338 gr. of scandium malate, dried in a vacuum desiccator, left on ignition 



2-667 gr. of scandia, = 1727 gr. of scandium. 



Theory. Experiment. 



(1). (2). 



21-24 20-71 



211-156 100-00 100-00 lOO'OO 



SCANDIUM FUMARATE, 



CHCCKX 



II NSc(OH) + iH 2 0. 



CHCOCY 



Fumaric acid is neutralised with dilute ammonia, and to the warm solution is added 

 an equivalent quantity of scandium sulphate. A white precipitate comes down, which 

 partially re-dissolves on cooling. Scandium fumarate, therefore, like so many other 

 scandium salts, is more soluble in cold than in hot water. The liquid is well boiled, 

 kept for some time in a hot-water oven till the precipitate settles, then quickly 

 filtered and washed with boiling water. After drying in a desiccator at the ordinary 

 temperature, it is powdered and again exposed to dry air. Scandium fumarate is a 

 white powder, appearing under the microscope as very minute spheres, slightly soluble 

 in hot, more so in cold water, and easily soluble in ammonia. When heated to redness 

 in the air it decomposes quietly, leaving, after the carbon has burnt off, pure white 

 scandia. 



The salt is difficult to get to a constant weight ; it had to be heated to 105 in a 

 hot-air bath for many days, and the weight taken at intervals of five or six hours. 

 At the end of a fortnight it was still slightly losing weight. I am therefore inclined 

 to think that the half molecule of water may be due to water of crystallisation not 

 entirely driven off at 105. 



