Symbol

Tb

Atomic Number

65

Atomic Mass

158.9254

Family

Lanthanide (Rare Earth Metal) Pronunciation

TER-bee-um

Overview

Terbium is classified as a rare earth element. The term is misleading because terbium is more common than metals such as silver and mercury. The name "rare earth" meant something else to early chemists. It was used because the rare earth elements were very difficult to separate from each other. They were not "rare" in the Earth, but they were "rarely" used for anything.

Today, chemists have developed new ways of separating elements from each other. Terbium doesn't have a great many uses, but is easily available. One use is in television screens. It helps the screen display the colors more clearly.

Although the term "rare earth" is still used, the more proper name for terbium and its cousins is the lanthanides. The term lanthanide comes from the element lanthanum in Row 6 of the...