Appearance and Characteristics
Harmful effects:
Praseodymium is considered to be moderately toxic.
Characteristics:
Praseodymium is a soft, malleable, ductile, silvery metal. Praseodymium is one of the lanthanide rare earth metals. It forms a flaky black oxide coating (Pr6O11) in air. Unlike many metal oxide layers, this one does not protect the metal from further oxidation. The pale green sesquioxide, Pr2O3, is not stable in air. Praseodymium reacts with water to form praseodymium hydroxide plus hydrogen gas. Praseodymium usually exists as a trivalent ion, Pr3+, in its compounds. Most of its salts are pale green in color.
Uses of Praseodymium
Praseodymium is used in high-intensity permanent magnets, which are essential in electric motors and generators used in hybrid cars and wind turbines.
Praseodymium is used in nickel metal hydride (NiMH) rechargeable batteries for hybrid automobiles. The negative electrode (cathode) in NiMH batteries is a mixture of metal hydrides – typically a rare earth misch metal hydride containing praseodymium, neodymium, lanthanum and cerium.
The metal is used as an alloying agent with magnesium creating a high-strength metal for aircraft engines. Praseodymium is used to make specialized yellow glass goggles for glass blowers and welders. Flame lighter flints use misch metal (a rare earth alloy) containing praseodymium to produce sparks by friction. Praseodymium salts are used to color glasses and enamels. Praseodymium is also used in the core of high-intensity carbon arc lights used by the film industry and in floodlighting.