Scandium

Scandium (Sc) is a rare-earth metal belonging to Group 3 of the periodic chart. Scandium is a silvery white metal that is reasonably soft. It is fairly stable in the air. But due to the production of Sc2O3
oxide on the surface, it will gradually change colour from silvery white to a yellow. In diluted acids, the metal dissolves slowly—except in hydrofluoric acid (HF), where a protective layer of trifluoride blocks further reactivity. From 0 K (460 °F or 273 °C ) until its melting point (2,806 °F or 1,541 °C), Scandium is paramagnetic. At pressures reaching 186 kilobars, it becomes superconducting at 459.6 °F (273.1 °C)

History

After Russian chemist Dmitry Ivanovich Mendeleyev predicted the existence of this element in 1871, Swedish chemist Lars Fredrik Nilson discovered its oxide, scandia, in the rare-earth minerals euxenite and gadolinite in 1879. Swedish chemist Per Teodor Cleve identified scandium as the hypothetical ekaboron later that year. Many heavy lanthanide ores, as well as tin, tungsten ores, and uranium, contain slight amounts of scandium, typically less than 0.2 percent.

Occurrence

Scandium only appears in nature as a stable isotope - scandium-45. Scandium-46 (half-life of 83.79 days) is the most stable of 25 radioactive isotopes. Its mass ranges from 36 to 61 (excluding nuclear isomers). Scandium-39 is the least stable (half-life of less than 300 nanoseconds).

Scandium is separated from the other rare earths by precipitation of the insoluble potassium scandium sulphate or diethyl ether extraction of scandium thiocyanate. In 1938, the metal was created by electrolyzing potassium, scandium chlorides, and lithium in a eutectic mixture.

Scandium is presently mostly generated as a by-product of uranium extraction from the mineral davidite, which contains approximately 0.02 percent scandium oxide. Scandium can be found in two different allotropic forms. At room temperature, the -phase is a close-packed hexagonal with a = 3.3088 and c = 5.2680.

Applications of scandium

• Only a few applications for this peculiar transition metal have been developed, owing to scandium's expensive price and scarcity.
• Because of its high melting point and low density, it might be used to alloy lightweight metals for military and high-performance purposes.
• Scandium is primarily used as an alloy addition in aluminum-based sports goods alloys and in high-intensity metal halide lamps.
• Scandium reduces high-temperature grain development when alloyed with aluminium and aluminum-based alloys.

Scandium's chemistry is more similar to that of other rare-earth elements with oxidation state +3 than to that of titanium or aluminium. Because of its substantially smaller ionic radius (1.66 for coordination number 12) than the rare-earth average (1.82 for coordination number 12), some of its behaviour is atypical among rare earths. As a result, the Sc3+ ion is a rather powerful acid with a high proclivity for forming complex ions.

Scandium-Related Information

• Lars Fredrik Nilson, the metal's discoverer, named it after Scandinavia in 1879.
• 99.9% of the metal was not separated until 1960.
• The metal is the planet's fiftieth most prevalent element.
• Dmitri Mendeleev predicted its presence 10 years before its actual discovery in the Mendeleev periodic table.
• Scandium is made up of thirteen different isotopes.
• The half-life of most isotopes of this metal is less than two minutes.