In 1885, Austrian chemist Carl Auer von Welsbach cracked a mystery. A substance called "didymium" was not one element but two. He split it and named the green half "praseodymium" — Greek for "green twin." The other half became neodymium.
Today praseodymium is essential for super-strong magnets. It boosts heat resistance in electric car motors and wind turbine generators. Its compounds also give glass a unique yellow-green tint that no other element can produce.
Praseodymium belongs to the rare earth elements, but it is not actually rare. Earth's crust contains more praseodymium than lead or tin. The real challenge is extraction — it never forms its own deposits and must be separated from other lanthanides.
Most reserves sit in monazite and bastnaesite sands. China produces over 60% of the world's supply. Praseodymium is critical for green energy — magnets containing it improve efficiency in electric motors and generators for wind power.
Praseodymium powder is pyrophoric — it can ignite spontaneously in air at around 200 °C. Metal shavings may catch fire from friction during machining. Bulk metal is safer but should be stored in sealed containers under argon. Praseodymium compounds have low toxicity, but fine dust irritates eyes and airways. Safety goggles, gloves, and proper ventilation are required.
The name "praseodymium" means "green twin" in Greek. Its salts have a vivid green color, and it was discovered alongside its "sibling" neodymium when the fake element didymium was split apart.
Praseodymium oxide glass filters out yellow sodium glare at 589 nm. Welders wear goggles made with this glass — it blocks the blinding flash while keeping everything else crisp and clear.
Replacing some neodymium with praseodymium in NdFeB magnets raises their working temperature to 200 °C. That is essential for EV motors, where magnets get scorching hot under load.
The alloy "mischmetal" contains about 5% praseodymium. It is the spark-making rod inside every flint lighter — a quick scrape sends a shower of sparks flying.
Praseodymium has just one stable isotope: Pr-141. That is unusual — most elements have at least two. Every praseodymium atom on Earth has exactly 82 neutrons.
For over 40 years, scientists believed "didymium" was a single element. Only in 1885 did Welsbach prove it was actually a mix of two different metals — praseodymium and neodymium.
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
141Pr | 140.907653 | 100.00% | stable | — |
Separation from didymium