njsas-home  periodic-table
< 64 65 Tb Terbium 66 >
     
64
Gd
157.3
65
Tb
158.9
66
Dy
162.5
96
Cm*
247
97
Bk*
247
98
Cf*
249
Atomic Number: 65
Atomic Radius: 178.2 pm
Atomic Symbol: Tb
Melting Point: 1356 șC
Atomic Weight: 158.9254
Boiling Point: 3230 șC
Electron Configuration: [Xe]6s24f9
Google text, images

History

(Ytterby, a village in Sweden) Discovered by Mosander in 1843. Terbium is a member of the lanthanide or "rare earth" group of elements. 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.

Production

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 earth metals, 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 1289oC. 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.

Cost

The element is priced at about $30/g (99.9%).

Handling

Little is known of the toxicity of terbium. It should be handled with care as with other lanthanide elements.


Copyright © UC 2003