From Chemistry Resource
Jump to: navigation, search

This is terbium.

Symbol Tb
Atomic number 65
Atomic mass 158.9254 amu

Terbium, discovered in 1843, is a soft, ductile, malleable and silvery element of the lanthanide series.

Distinguishing properties

Terbium is extremely reactive when exposed to air or oxygen and must be kept in an inert atmosphere.


Terbium is a rare-earth metal occurring in low concentration in monazite sand, which is a mixture of phosphate of calcium, thorium, cerium, and most of the other rare-earths. This sand is often 50% rare-earth by mass and about 0.03% terbium. Other sources of terbium are oxide mixtures found in xenotime and euxenite. Such oxide mixtures often contain up to 1% terbium.


Terbium is used in special lasers and as a dopant in solid-state devices.

See also

Periodic table of the elements