Niobium (Nb)

Niobium (symbol Nb) is the chemical element with atomic number 41: a transition metal, solid at 0 °C, with an atomic mass of 92.906 u. Discovered in 1801 (Charles Hatchett).

Niobium is a gray, ductile, tough metal, more than 85% of which goes into strengthening the steel of bridges, pipelines and cars. It becomes superconducting at very low temperatures and is used in the magnets of MRI scanners and of CERN's Large Hadron Collider. Brazil produces most of it.

Key facts

Atomic number: 41
Symbol: Nb
French name: Niobium
Atomic mass: 92.906 u
Molar mass: 92.906 g/mol
Family: Transition metals
Position: period 5, group 5, d-block
State at 0 °C: Solid
Melting point: 2,476.9 °C
Boiling point: 4,743.9 °C
Density: 8.57 g/cm³
Electronegativity (Pauling): 1.6
First ionization energy: 652 kJ/mol
Atomic radius: 145 pm
Electron configuration: [Kr] 4d⁴ 5s¹
Abundance in Earth's crust: 20 ppm (33rd most abundant element)
Indicative price: 73 $/kg (order of magnitude)
Radioactive: no
Discovery: 1801, Charles Hatchett

Origin of the name

From Niobe, daughter of Tantalus in Greek mythology.

What does niobium look like?

A shiny, light-gray metal, as ductile as mild steel. Anodizing (controlled oxidation) brings out iridescent colors on its surface, from blue to gold.

Where is niobium found?

About 20 ppm of Earth's crust. It is concentrated in rare rocks called carbonatites, such as the giant Araxá deposit in Brazil, and accompanies tantalum in coltan.

Natural sources

Pyrochlore
Columbite
Coltan (columbite-tantalite)

How is niobium produced?

Pyrochlore is concentrated and then reduced with aluminium to make ferroniobium, an iron-niobium alloy added to steel. World output is about 100,000 tonnes of niobium a year, about 90% of it in Brazil.

Top producers

Brazil
Canada

What is niobium used for?

High-strength microalloyed steels (bridges, pipelines, car bodies).
Niobium-titanium superconducting magnets in MRI scanners and the LHC.
Superalloys for jet and rocket engines.
Superconducting cavities in particle accelerators.
Hypoallergenic jewelry and piercings.

In everyday life

Car bodies and steel beams
Hospital MRI scanner
Colorful piercing

Role in living things

No known biological role; it is poorly absorbed and has low toxicity.

Hazards of niobium

Low toxicity. As with many metals, fine dust can irritate and ignite.

Cosmic origin

Dying stars: Made slowly in red giants (stars like the Sun at the end of their lives).

History of niobium

In 1801, Englishman Charles Hatchett found a new element in a mineral from Connecticut and named it “columbium.” It was later confused with tantalum, until German chemist Heinrich Rose told them apart in 1844 and named it niobium, after Niobe, daughter of Tantalus in Greek mythology.

Did you know?

The double name niobium/columbium lasted more than a century: IUPAC settled it in 1949, but some American metallurgists still say columbium.
The Araxá mine in Brazil could single-handedly meet world demand for several centuries.
A few tenths of a percent of niobium is enough to make steel significantly stronger.

Isotopes of niobium

A single stable isotope, niobium-93. Long-vanished niobium-92 left traces in meteorites that shed light on the birth of the Solar System.

niobium-92: radioactive, half-life 3.47 × 10⁷ years. An “extinct” radioactivity whose traces date the formation of meteorites.
niobium-93: 100% of natural niobium, stable
niobium-94: radioactive, half-life 20,300 years. Formed in reactor steels, it complicates their decommissioning.
niobium-95: radioactive, half-life 35 days

Related elements

Same family (transition metals): Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), Yttrium (Y), Zirconium (Zr), Molybdenum (Mo), Technetium (Tc), Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Silver (Ag), Cadmium (Cd), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os), Iridium (Ir), Platinum (Pt), Gold (Au), Mercury (Hg), Rutherfordium (Rf), Dubnium (Db), Seaborgium (Sg), Bohrium (Bh), Hassium (Hs).

Same column (group 5): Vanadium (V), Tantalum (Ta), Dubnium (Db).