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.