Praseodymium
Praseodymium produces the yellow-green colour in some heat-resistant glass and is a key component of the powerful neodymium-praseodymium-iron-boron magnets used in wind turbines and electric motors.
- Atomic Number5959 protons, 59 electrons
- Atomic Mass140.90766 u59× heavier than hydrogen
- State at Room TempSolidSolid
- Density6.77 g/cm³
- Melting / Boiling930.9°C / 3519.8°C
- Discovered1885
What is Praseodymium?
Praseodymium is a soft, silvery-white lanthanide with 59 protons. Its name comes from the Greek prasios didymos meaning green twin, because praseodymium gives a characteristic green-yellow colour to its compounds and glass.
Praseodymium was separated from didymium (a mixture thought to be a single element) by Carl Auer von Welsbach in 1885.
Where you find Praseodymium
On Earth
China, USA, Australia (bastnäsite, monazite deposits).
How we use Praseodymium
- Praseodymium is mixed with neodymium in the most powerful permanent magnets, used in wind turbines and electric vehicle motors.. High-strength magnets
- Praseodymium oxide makes a strong yellow-green ceramic pigment used in tiles and porcelain.. Ceramic pigments
- Adding praseodymium to glass absorbs UV radiation and protects eyes from welding arc glare in protective goggles.. Protective glass
How it was discovered
Praseodymium was separated from didymium (a mixture thought to be a single element) by Carl Auer von Welsbach in 1885.
Deeper dive: praseodymium and the lanthanide series
The lanthanides (elements 57-71) are characterised by the progressive filling of the 4f electron subshell. Because the 4f electrons are deep inside the atom and shielded by outer electrons, they have little effect on chemical bonding. All lanthanides have very similar chemical behaviour, forming +3 ions of comparable size. This similarity makes them extraordinarily difficult to separate from each other, historically requiring hundreds of fractional crystallisation steps. Ion exchange chromatography and solvent extraction methods, developed in the 1940s, finally made pure lanthanides available in quantity.
The term "rare earth" is historically misleading. Most lanthanides are as abundant as copper or nickel in the Earth's crust. The challenge is not scarcity but concentration: they are geochemically dispersed and rarely form rich mineral deposits. The name stuck from the 18th century when they were genuinely difficult to isolate.
Moving to 60 protons brings us to the next element in this remarkable family.