SIR WILLIAM CROOKES ON SCANDIUM. 385 



solution scandium acetate is added and the whole boiled. On cooling, scandium 

 octamethyltetraminodihydroxyparadixanthyl benzene tetracarboxy late comes down a 

 a red powder, insoluble in cold water. 



Analysis. 



3-167 gr. of scandium octamethyltetraminodihydroxyparadixanthyl benzene tetra- 

 carboxylate left on ignition 0'57G gr. of scandia, = Q'3730 gr. of scandium. 



Theory. Experiment. 



Sc 5 220-50 11-41 1178 



CggHAc.Ns. . . 171171 88-59 88"22 



1932-21 100-00 100-00 



More than once I have been asked why I chose such very out-of-the-way acids 

 wherewith to prepare scandium salts ? I give my chief reason : Attempts on several 

 occasions have been made to discover a means of separating some of the " rare earths " 

 from their companions by forming compounds with weak organic acids. Thus, in 

 1897, KOSMANN* employed citric acid in the separation of thoria. URBAlNt used 

 acetylacetonate of sodium for the same purpose. METZGEEJ tried maleic acid, cinnamic 

 acid, picric acid, phthalic acid, and fumaric acid. He found fumaric acid effectual in 

 separating thoria from the other earths in monazite, whilst the other acids also gave 

 partial separations, although not complete. 



In 1904, NEISH tried many organic acids for the separation of the rare earths, 

 chiefly thoria. Among other acids, he tried gallic, tannic, citric, salicylic, oleic, 

 linoleic, paratoluic, oxyisophthalic, benzoic, meta-, ortho-, and para-nitrobenzoic, and 

 fumaric. Of these the metanitrobenzoic acid proved most effectual, the process being 

 capable of accurate quantitative results. It was found that other rare earths besides 

 thoria behaved differently towards these acids, but the variation was not sufficient to 

 enable the reactions to be used for accurate separations. 



Soon after those experimental papers appeared I commenced similar researches 

 hoping to find an organic reagent which would be a precipitant for some of the yttria 

 earths if not with quantitative accuracy, at all events with sufficient separation to 

 allow a fractionation method to be based on the reaction. My results, not being 

 sufficiently definite, were never published ; but as the organic acids were in my 

 laboratory when the scandium research was commenced, I preferred to use these acids, 



* 'Chem. Central!).,' 1897, Part I., 837; 'Chemical News,' Ixxxvi., 218. 

 t ' Bull. Soc. Chim.,' 1896, xv., 347. 



t ' Journ. Am. Chem. Soc.,' xxiv., No. 10; 'Chemical News,' Ixxxvi., 218, 229, 242. 

 'Journ. Am. Chem. Soc.,' xxvi., No. 7; 'Chemical News,' xc., 196, 201. 

 VOL. CCX. A. 3 D 



