Terbium

History

Occurence

• It is found in cerite, gadolinite, and other minerals along with other rare earths.
• It is recovered commercially from monazite in which it is present to the extent of 0.03%, from xenotime, and from euxenite, a complex oxide containing 1% or more of terbia.
• Terbium has been isolated only in recent years with the development of ion-exchange techniques for separating the rare-earth elements.
• As with other rare earths, it can be produced by reducing the anhydrous chloride or fluoride with calcium metal in a tantalum crucible.
• Calcium and tantalum impurities can be removed by vacuum remelting.
• Other methods of isolation are possible.

Properties

• Terbium is reasonably stable in air.
• It is a silver-gray metal, and is malleable, ductile, and soft enough to be cut with a knife.
• Two crystal modifications exist, with a transformation temperature of 1289C.
• Twenty one isotopes with atomic masses ranging from 145 to 165 are recognized.
• The oxide is a chocolate or dark maroon color.

Uses

• Sodium terbium borate is used in solid-state devices.
• The oxide has potential application as an activator for green phosphors used in color TV tubes.
• It can be used with ZrO2 as a crystal stabilizer of fuel cells which operate at elevated temperature.
• Few other uses have been found.

Costs