SCANDIUM

Name: Scandium (referring to the Scandinavian Peninsula)

Symbol: Sc

Group: 3

Period: 4

Block: d

Category: Transition metals

Atomic number: 21

Atomic mass: 44.955 u

Electrons per shell: 2, 8, 9, 2

Electronegativity: 1.36

Density: 2.985 g/cc

Melting point: 1541ºC

Boiling point: 2836ºC

Thermal conductivity: W (m·K)

Electrical conductivity: 1.8 × 10^6 S/m

Magnetic order: Paramagnetic

Ordinary state: Solid

Oxidation states: 1, 2, 3

Mohs hardness: 2.5

Vickers Hardness: No data

Brinell Hardness: 750 MPa

Most stable isotopes: Sc-45 (100%, monoisotopic element)

Discoverer: Lars Friedrik Nilson, Swedish (1879)

Scandium (Sc), a transition metal with atomic number 21, was discovered in 1879 by the Swedish chemist Lars Fredrik Nilson while he was researching rare earth elements. However, its story actually begins a few years earlier with the Russian chemist Dmitri Mendeleev. In 1871, Mendeleev published his work on the periodic table of elements, in which he left an empty space for an as-yet-undiscovered element. Based on the position of that space, he predicted that the new element, which he called ekaboron, would have an atomic weight of approximately 44 and chemical properties similar to those of boron and aluminum. Mendeleev's prediction was a bold act at a time when science had not yet fully accepted the notion of undiscovered elements.

The brilliance of Mendeleev's prediction was confirmed when, eight years later, Lars Fredrik Nilson isolated a new element from the minerals euxenite and gadolinite, which he found in Scandinavia. Nilson determined that the properties of this new element almost perfectly matched Mendeleev's predictions for ekaboron. In honor of its place of origin, Nilson named it scandium, derived from the Latin word Scandia, meaning "Scandinavia". Although Nilson managed to obtain a small amount of scandium oxide (Sc₂O₃), the pure metal was extremely difficult to isolate. It was not until 1937 that scientists W. Fischer, K. Brünger, and H. G. Morawietz succeeded in producing pure metallic scandium for the first time through the electrolysis of molten scandium, potassium, and lithium chloride. This achievement marked the end of scandium's long journey, from a theoretical prediction to a tangible reality.

Scandium (Sc), whose name comes from Scandinavia, the region where it was first discovered and isolated, is considered the lightest transition metal due to its atomic number of 21. Although formally classified as such, its physical and chemical properties make it more similar to the lanthanides or "rare earths", and in fact, it is often found in minerals containing these elements.

This metal is remarkably soft and ductile, but it has a high affinity for oxygen (O), which makes it very reactive. Its low popularity and rarity are due to its scarcity and the difficulty of its extraction. The refinement process of pure scandium is complex and expensive, which limits its applications to very specific and high-value uses.

From a metallurgical point of view, scandium is a highly sought-after alloying element, especially in the aerospace industry. Most of its production is destined for the creation of aluminum-scandium alloys, which are extremely light, yet very strong and corrosion-resistant. These properties make them ideal for manufacturing components for high-performance aircraft and space vehicles. In combination with titanium (Ti), scandium forms hard and thermally stable alloys, essential for parts that must withstand extreme temperatures.

In addition to its use in the aerospace industry, scandium is used in the manufacture of high-performance bicycle frames, where its ability to combine lightness with strength is a competitive advantage. It is also part of some ultra-light superalloys that are advertised as "as light as aluminum, stronger than titanium, and with excellent corrosion resistance."

Scandium (Sc), despite its scarcity and high cost, is a valuable metal in metallurgy due to its ability to drastically improve the properties of other alloys. Its primary use is in the manufacture of high-performance alloys, where its addition, even in small quantities, produces significant results.

The main use of scandium is in aluminum-scandium alloys, considered elite for their lightness and strength. The addition of just 0.5% scandium to aluminum improves its strength, toughness, and weldability. This allows for the construction of lighter and more robust structures, crucial for the aerospace industry. For example, NASA has used these alloys in the manufacturing of components for space vehicles, where weight savings are vital for performance and fuel efficiency. Similarly, they are used in parts for high-performance aircraft and in the manufacture of bicycle frames, baseball bats, and high-end fishing rods, where the combination of lightness and durability is a key factor.

In addition to aluminum alloys, scandium forms alloys with other metals, such as titanium (Ti). These titanium-scandium alloys are exceptionally hard and thermally stable, making them suitable for engine components and structures that operate at high temperatures. Scandium is also a component in some ultra-light superalloys, which are designed to be as light as aluminum but with superior strength to titanium and excellent corrosion resistance, making them very valuable in military and advanced engineering applications. In summary, the utility of scandium in metallurgy is based on its ability to transform the properties of alloys, enabling the creation of more efficient and resistant materials for the most demanding industries.