- Atomic Radius (Å)
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.
41 Atomic Number
92.91 u Atomic Mass
2741.15 K Melting Point
5017 K Boiling Point
8.57 g/cm³ Density
2.1 Å Atomic Radius
1.64 Å Covalent Radius
1.6 Electronegativity
6.76 eV First Ionization Energy
88.52 Electron Affinity
5 Number of Shells
2, 8, 18, 12, 1 Electron Shell Occupations
0.27 J/g Specific Heat