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David

Darling

terbium

terbium

Terbium. Image copyright: smart-elements.com.


Terbium (Tb) is a silver-gray metallic element of the lanthanide series. Discovered in 1843, it is found in such minerals as monazite, gadolinite, and apatite. The soft element is used in semiconductors; sodium terbium borate is used in lasers. Its single natural isotope is 159Tb .

 

atomic number 65
relative atomic mass 158.925
relative density 8.234
melting point 1,360°C (2,480°F)
boiling point 3,041°C (5,506°F)