Answer: ytterbium

AnswerCrossword Clue
YTTERBIUMMetallic element
YTTERBIUMSilvery metallic element
YTTERBIUMOne of the rare earths
ytterbium(Swedish) a rare element of the boron group
ytterbiumThe chemical element of atomic number 70, a silvery-white metal of the lanthanide series