Niobium (Columbium) Chemical and Physical Properties

Niobium, like tantalum, can act as an electrolytic valve allowing alternating current to pass in only one direction through an electrolytic cell. Niobium is used in arc-welding rods for stabilized  grades of stainless steel. It is also used in advanced airframe  systems. Superconductive magnets are made with Nb-Zr wire, which retains superconductivity in strong magnetic fields. Niobium is used in lamp filaments and to make jewelry. It is capable of being colored by an electrolytic process. Niobium (Columbium)  Basic Facts Atomic Number: 41Symbol: Nb (Cb)Atomic Weight: 92.90638Discovery: Charles Hatchet 1801 (England)Electron Configuration: [Kr] 5s1 4d4 Word Origin:  Greek mythology: Niobe, daughter of Tantalus, as niobium is often associated with tantalum. Formerly known as Columbium, from Columbia, America, the original source of niobium ore. Many metallurgists, metal societies, and commercial producers still use the name Columbium. Isotopes: 18 isotopes of niobium are known. Properties: Platinum-white with a bright metallic luster, although niobium takes on a bluish cast when exposed to air at room temperatures for a long time. Niobium is ductile, malleable, and highly resistant to corrosion. Niobium does not naturally occur in the free state; it is usually found with tantalum. Element Classification: Transition Metal Niobium (Columbium) Physical Data Density (g/cc): 8.57Melting Point (K): 2741Boiling Point (K): 5015Appearance: shiny white, soft, ductile metalAtomic Radius (pm): 146Atomic Volume (cc/mol): 10.8Covalent Radius (pm): 134Ionic Radius: 69 (5e)Specific Heat (20 °C J/g mol): 0.268Fusion Heat (kJ/mol): 26.8Evaporation Heat (kJ/mol): 680Debye Temperature (K): 275.00Pauling Negativity Number: 1.6First Ionizing Energy (kJ/mol): 663.6Oxidation States: 5, 3Lattice Structure: Body-Centered CubicLattice Constant (Ã…): 3.300 Sources Los Alamos National Laboratory (2001)Crescent Chemical Company (2001)Langes Handbook of Chemistry (1952)CRC Handbook of Chemistry Physics (18th Ed.)