scandium

Scandium is a chemical element with the symbol Sc and atomic number 21. It is a lightweight transition metal with a silvery appearance that tarnishes in air. In nature it is rare and not found as a free metal; it occurs mainly in trace amounts in minerals such as thortveitite (Sc2Si2O7) and gadolinite and is typically recovered as a byproduct of refining other metals, including rare earth elements and uranium ores. The most common oxidation state is +3, and scandium forms compounds such as scandium oxide (Sc2O3) and various salts.

Discovery and name: Scandium was identified in 1879 by Swedish chemist Lars Fredrik Nilson while studying gadolinite. He named the element after Scandinavia.

Occurrence and production: Commercial production is limited and relatively expensive. Scandium is typically obtained by reducing scandium oxide with calcium or by electrolytic methods starting from scandium salts. Global supply comes from a few producers and is often linked to the processing of other minerals.

Uses: The principal application is as an alloying agent in aluminum-scandium alloys, which offer higher strength and improved creep resistance with very low density. These alloys are used in aerospace, high-performance engines, and sporting equipment. Scandium compounds are also employed in specialty ceramics, catalysts, and certain high-intensity lighting applications, including metal-halide lamps and phosphors.

Biology and safety: Scandium has no known essential biological role. It is not considered highly toxic, but as a reactive metal in powder form it requires standard handling precautions.