Praseodymium
Praseodymium is a soft malleable, silvery-yellow metal. It is a member of the lanthanide group of the periodic table of elements. It reacts slowly with oxygen: when exposed to air it forms a green oxide that does not protect it from further oxidation. It is more resistant to corrosion in air the other rare metals, but it still needs to be stored under oil or coated with plastic. It reacts rapidly with water.