Category: Transition metal
Atomic Number: 21
Period: 4 | Group: 3
Block: d-block
A rare-earth-adjacent metal that makes aluminium alloys far stronger, at a price that keeps it exotic.
| Property | Value |
|---|---|
| Phase at STP | Solid |
| Density | N/A |
| Melting Point | 1814.00 K (1540.85 °C) |
| Boiling Point | 3109.00 K (2835.85 °C) |
| Heat Capacity | N/A |
| Property | Value |
|---|---|
| Atomic Mass | 44.9559 u |
| Electronegativity (Pauling) | N/A |
| Oxidation States | +3 |
| Electron Configuration |
| Discovered By | Unknown |
|---|---|
| Discovery Year | 1879 |
| Named After | Latin Scandia, Scandinavia |
Mendeleev's eka-boron (1871)
When Dmitri Mendeleev developed his periodic table, he left a gap between calcium and titanium and predicted an element he called eka-boron, with an atomic weight between theirs and an oxide of the formula Eb₂O₃.
Nilson finds scandium (1879)
In 1879 the Swedish chemist Lars Fredrik Nilson, analyzing the rare minerals euxenite and gadolinite from Scandinavia, found a new oxide whose spectrum matched no known element. He named the element scandium, after Scandinavia.
The prediction confirmed
Later in 1879 Per Teodor Cleve showed that scandium had the properties Mendeleev had predicted for eka-boron. Together with gallium (1875) and germanium (1886), it was one of the first confirmations of the periodic table.
The metal (1937)
Metallic scandium was first produced in 1937, by electrolysis of a molten mixture of potassium, lithium and scandium chlorides. Industrial use began only in the 1970s and 1980s, when its effect on aluminum alloys was found.
| ISOTOPE | Neutrons | Natural Abundance | Half-life | Decay Mode |
|---|---|---|---|---|
| Sc-45 | 24 | 100% | Stable | - |
Data: IAEA Nuclear Data Section, LiveChart of Nuclides, ground-state evaluations, retrieved October 10, 2026. Abundance is the share of atoms in the natural element; a dash means the isotope has no standard natural abundance.
Aluminum-scandium alloys
The main use of scandium metal is in aluminum alloys. Adding a few tenths of a percent of scandium refines the grain of the aluminum, making it stronger and easier to weld. These alloys are used in aerospace parts and in high-end sports equipment such as bicycle frames and baseball bats. The high price of scandium keeps them a specialty material.
Fuel cells and electronics
Solid oxide fuel cells: scandium oxide stabilizes zirconia electrolytes that conduct oxygen ions well at lower operating temperatures than other electrolytes.
Electronics: thin films of aluminum scandium nitride are used in radio-frequency filters for mobile phones.
Lighting and tracing
Metal halide lamps: scandium iodide in high-intensity discharge lamps produces light close to daylight, used for stadiums and film and television lighting.
Tracers: scandium-46 is used to follow the flow of materials in oil refineries.
| Earth's Crust | N/A |
|---|---|
| Universe | N/A |