atomic number 63

Thesaurus

Noun

1.

atomic number 63 - a bivalent and trivalent metallic element of the rare earth groupEu, europiummetal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.monazite - a reddish-brown mineral containing rare earth metals; an important source of thorium and cerium