鈳[金屬元素]
Columbium \Co*lum"bi*um\, n. [NL., fr. Columbia America.] (Chem.) A rare element of the vanadium group, first found in a variety of the mineral columbite occurring in Connecticut, probably at Haddam. Atomic weight 94.2. Symbol Cb or Nb. Now more commonly called {niobium}.
columbium n : a former name for niobium