Niobium Facts (Columbium)

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: 41
• Symbol: Nb (Cb)
• Atomic Weight: 92.90638
• Discovery: 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): 8.57
• Melting Point (K): 2741
• Boiling Point (K): 5015
• Appearance: shiny white, soft, ductile metal
• Atomic Radius (pm): 146
• Atomic Volume (cc/mol): 10.8
• Covalent Radius (pm): 134
• Ionic Radius: 69 (+5e)
• Specific Heat (@20°C J/g mol): 0.268
• Fusion Heat (kJ/mol): 26.8
• Evaporation Heat (kJ/mol): 680
• Debye Temperature (K): 275.00
• Pauling Negativity Number: 1.6
• First Ionizing Energy (kJ/mol): 663.6
• Oxidation States: 5, 3
• Lattice Structure: Body-Centered Cubic
• Lattice Constant (Å): 3.300

Sources

• Los Alamos National Laboratory (2001)
• Crescent Chemical Company (2001)
• Lange's Handbook of Chemistry (1952)
• CRC Handbook of Chemistry & Physics (18th Ed.)