====== Columbium ====== Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. The name comes from Greek mythology: Niobe, daughter of Tantalus since it is so similar to tantalum.([[https://en.wikipedia.org/wiki/Niobium|source]]) {{scribblenauts-unlimited:c:columbium.jpg}}