Scandium

Scandium opens the d-block: its atoms carry the configuration [Ar]3d1 4s2, just one electron in the 3d subshell. That lone d electron and the two 4s electrons are lost together, so scandium's chemistry is almost entirely that of the Sc3+ ion. Because Sc3+ has the electron arrangement of argon, with no d electrons left, its compounds are colorless and nonmagnetic, quite unlike the vividly colored salts of its neighbors. In practice scandium behaves more like aluminium, yttrium and the lanthanides than like a typical transition metal, and it is usually counted among the rare earth elements.

The metal is soft, silvery and light (2.99 g/cm3), melting at 1541 °C. Scandium is not especially scarce, at about 22 parts per million of Earth's crust, more than lead, but it almost never concentrates into rich ores, so world output is only a few tens of tonnes of oxide a year. Its most valuable use is in aluminium: adding 0.1 to 0.5 percent scandium creates tiny Al3Sc particles that pin the metal's grain structure, raising strength and making welds far less prone to cracking.

Discovery

Dmitri Mendeleev predicted an element he called eka-boron in 1871. In 1879 the Swedish chemist Lars Fredrik Nilson found a new oxide while analyzing the Scandinavian minerals euxenite and gadolinite, and named the element after Scandinavia (Latin Scandia). His colleague Per Teodor Cleve soon showed that its properties matched Mendeleev's eka-boron. Metallic scandium was first produced in 1937 by electrolysing a molten mixture of potassium, lithium and scandium chlorides.