Praseodymium
lanthanideProperties
| Property | Value |
|---|---|
| Atomic Mass | 140.91 amu |
| Category | lanthanide |
| Period | 6 |
| Electron Configuration | [Xe] 4f3 6s2 |
| Electronegativity | 1.13 (Pauling) |
| Oxidation States | 3, 4 |
| Melting Point | 1208 K (934.9 °C) |
| Boiling Point | 3793 K (3519.8 °C) |
| Density | 6.77 g/cm³ |
| Discovered By | Carl Auer von Welsbach (1885) |
About Praseodymium
Praseodymium's name means 'green twin' in Greek — a nod to the apple-green color of Pr₂O₃ and to the fact that for half a century chemists thought it and neodymium were a single element called didymium. Carl Auer von Welsbach finally pulled them apart in 1885 by fractional crystallization of the double ammonium nitrates. The metal itself is silvery and so reactive that a freshly cut surface develops a flaky green oxide layer within minutes, which is why lab samples sit under mineral oil. Coordination chemistry is dominated by Pr³⁺ — colorless yellow-green hydrated salts that hydrolyze gradually in water — but the +4 state shows up in mixed oxides like Pr₆O₁₁, where roughly a third of the praseodymium atoms have given up a fourth electron. That mixed-valence behavior is what makes praseodymium pigments such intense yellow colorants in zircon ceramics.
Fun Fact
Didymium glass — a Pr/Nd mix in soda-lime — has a sharp absorption notch at the 589 nm sodium D-line. Glassblowers' safety lenses use it because the yellow flare from hot soda glass is exactly the wavelength didymium swallows, and what's left is the colour of the glass itself.
Common Uses
- Yellow Pr-doped zircon pigments for ceramic tiles and tableware
- Didymium safety lenses that absorb the 589 nm sodium D-line for glassblowers
- Substitutes for or supplements neodymium in NdFeB sintered magnets
- Praseodymium-doped fluoride fiber amplifiers operating in the 1.3 µm telecom window
- Mischmetal component in lighter flints alongside cerium and lanthanum
- Single-crystal nickel superalloys for high-pressure turbine blades