SCANDIUM [symbol Sc, atomic weight 44.1 (O=16)], one of the rare earth metals. It was isolated in 1879 by L. F,. Nilson and was shown by Cleve to be identical with the ekaboron predicted by D. Mendeléeff. The separation of scandium from wolframite (which contains 0.14-0.16% of rare earths) is given by R. J. Meyer (Zeit. anorg. Chem. 1908, 60, p. 134), but it seems impossible to obtain a perfectly pure specimen of the oxide. The salts of scandium are all colourless, the chloride and bromide corresponding in composition to Sc2X6⋅12H2O; the fluoride is anhydrous. The sulphate combines with the alkaline sulphates to form double salts of the type Sc2(SO4)3⋅3K2SO4. A large number of salts, both of inorganic and organic acids, have been described by Sir W. Crookes (Phil. Trans. 1908, 209, A. p. 15); those of the fatty acids are in most cases more soluble in cold than in hot water.