See also:

• Science: Chemistry: Elements: Transition Metals  (3)
• Science: Technology: Metallurgy  (51)

ChemGlobe: Niobium - - Electronic, thermal, and steric data along with a table of isotopes.

ChemicalElements.com: Niobium - - Basic information, atomic structure, and isotopes.

EnvironmentalChemistry.com: Niobium - - Atomic structure, chemical and physical properties, and table of nuclides.

It's Elemental: Niobium - - Basic physical and historical information.

LANL: Niobium - - History, sources, properties, and uses.

Lenntech: Niobium - - Physical data, chemical properties, and health effects.

USGS Minerals Information: Niobium - - Statistics and information on the worldwide supply, demand, and flow of the element (PDF format).

Visual Elements: Niobium - - Image, uses, general information, and ionisation energies.

WebElements: Niobium - - Extensive information on history, uses, occurrence, compounds, and properties of the element.

Wikipedia: Niobium - - Properties of the element, including its history, applications, and characteristics.