Scandium

Scandium (chemical symbol Sc, atomic number 21) is a silver-white, lightweight transition metal classified as a rare-earth element. It is represented by the symbol "Sc" and occurs naturally on Earth. Russian chemist Dmitry Ivanovich Mendeleyev predicted it in 1871, and Lars Fredrik Nilson later discovered it in 1879. Scandium has the atomic number 21 and an atomic weight of 44.965 g/mol.

1.0Introduction

Scandium is a silvery-white, moderately soft metal relatively stable in air. However, over time, it tends to change from silvery white to a yellowish hue due to the formation of Sc₂O₃ oxide on its surface. Although it ranks as Earth's 50th most abundant element, it is the 23rd most abundant element in the Sun.

Due to the small size of its ions, scandium does not selectively bond with common ore-forming anions, resulting in concentrations rarely exceeding 100 ppm in nature.

2.0Physical Properties of scandium

3.0Chemical Properties of Scandium

Scandium exhibits several notable chemical behaviours:

• Reaction with Air: Scandium reacts rapidly, forming a white coating of scandium oxide (Sc₂O₃) and nitride (ScN). When exposed to water, scandium ignites with a yellow-red flame as Sc₂O₃ is formed:4Sc(s)+3O2(g)→2Sc2O3(s)
• Reactivity with Acids: Scandium dissolves readily in weak acids, except in hydrogen fluoride (HF), where a protective layer of scandium trifluoride (ScF₃) forms, preventing further reaction.
• Reaction with Halogens: Scandium reacts with halogens to form the corresponding trihalides, such as scandium chloride (ScCl₃) and scandium bromide (ScBr₃):

2Sc(s) +3Cl₂₍g)→2ScCl₃(s)

2Sc(s)+3Br₂(g)→2ScBr₃(s)

• Reaction with Hydrochloric Acid:

Scandium dissolves rapidly in diluted HCl, producing aquated Sc(III) ions and releasing hydrogen gas.

2Sc(s) + 6HCl(aq) → 2Sc³⁺⁽aq) + 6Cl⁻(aq) + 3H₂(g)

These properties highlight scandium's reactivity with halogens, oxygen, and acids and its ability to mix to form compounds like trihalides. 

4.0Uses of Scandium

Scandium has several valuable applications, especially in high-performance and industrial settings:

• Alloying Agent: Because of its low density and high melting point, Scandium is frequently employed as an alloying agent with light metals, especially in high-performance and military applications; it fortifies materials without significantly increasing their weight. 
• Sporting Goods: Scandium-aluminium alloys produce lightweight, high-performance materials for products like baseball bats, tent poles, bicycle frames, and other sporting equipment where strength and light weight are critical.
• Metal Halide Lamps: Scandium is an alloy additive in high-intensity metal halide lamps. Adding scandium iodide to mercury vapour lamps makes them more efficient. It produces light similar to natural sunlight, making it ideal for television recording indoors or at night for accurate colour reproduction.
• Scandium-46 Isotope: The radioactive isotope scandium-46 is used as a tracer in oil refining processes to track the movement of different fractions. It is also employed to detect leaks in underground pipelines.