europium science definition

A very rare, silvery-white metallic element that is the softest member of the lanthanide series. It is used in making color television tubes and lasers and as a neutron absorber in nuclear research. Atomic number 63; atomic weight 151.96; melting point 826°C; boiling point 1,439°C; specific gravity 5.259; valence 2, 3. See Periodic Table.