Scandium (Sc)

Description

Basic Information

• Element Name: Scandium

• Symbol: Sc

• Atomic Number: 21

• Atomic Weight: 44.96

• Element Category: Transition Metal (Group 3), often grouped with Rare Earth Elements due to similar properties

• Standard State: Solid

• Appearance: Silvery-white, lightweight, and soft metal

Chemical and Physical Properties

• Density: 2.985 g/cm³

• Melting Point: 1,541 °C (2,806 °F)

• Boiling Point: 2,836 °C (5,137 °F)

• Electronegativity (Pauling scale): 1.36

• Oxidation State: +3 (dominant)

• Magnetism: Paramagnetic

• Reactivity: Readily forms oxide layer in air; reacts with water and acids

Storage and Stability

Scandium is relatively reactive, forming a yellowish or pink oxide layer when exposed to air. For storage, it is typically kept in sealed containers or under oil or inert atmosphere. It is non-toxic and environmentally stable in small quantities.

Occurrence and Extraction

• Scandium is a relatively rare element in Earth’s crust, not found in concentrated ores

• Occurs in trace amounts in thortveitite, euxenite, monazite, bauxite, and as a byproduct of uranium or titanium production

• Extraction is complex and costly, requiring advanced solvent extraction, ion-exchange, or hydrometallurgical techniques

Isotopes

• Naturally occurring scandium is mono-isotopic, consisting of only Sc-45

• Several radioactive isotopes exist, but are primarily used in research

Key Applications

1. Aerospace and High-Strength Alloys

• Scandium–aluminum alloys (Al-Sc) significantly enhance:

  • Strength-to-weight ratio

  • Weldability

  • Fatigue resistance

• Used in:

  • Aerospace components (e.g., aircraft frames)

  • Missile systems

  • Sports equipment (e.g., baseball bats, bicycle frames)

2. Solid Oxide Fuel Cells (SOFCs)

• Sc₂O₃ (scandium oxide) is used as a stabilizer for zirconia electrolytes, improving conductivity and thermal stability

  • Ideal for stationary energy systems and distributed power generation

3. Lighting and Optics

• Scandium iodide is used in metal-halide lamps to produce light similar to natural sunlight

  • Applications include:

    • Film and television lighting

    • Stadium floodlights

    • High-intensity lamps for industrial use

4. 3D Printing and Advanced Manufacturing

• Scandium-containing alloys are gaining use in additive manufacturing (AM)

  • Offers fine grain structure, high thermal performance, and ideal for complex, high-strength parts

5. Electronics and Ceramics

• Scandium oxide is used in:

  • Electronic ceramics

  • Piezoelectric devices

  • Lasers and sensors

Strategic and Industrial Relevance

• Scandium is classified as a critical material due to:

  • High value in lightweight alloys and clean energy

  • Limited global supply and production capacity

• Global production is extremely limited (<50 tons/year), with Russia, China, Ukraine, and Australia being key players

• Emerging demand in green aviation, hydrogen fuel, and EV applications

Interesting Facts

• Discovered in 1879 by Swedish chemist Lars Fredrik Nilson

• Named after Scandinavia

• Though abundant in trace amounts, economic deposits are rare

• A small addition of 0.1%–0.5% Scandium to aluminum dramatically improves alloy performance

• The price of scandium is among the highest for rare earths due to its strategic value and rarity