Niobium - Nb
Niobium (Nb) is a chemical element with atomic number 41. This page summarises its properties, uses and environmental context, with notes for water and process-treatment engineers.
Properties · Uses and occurrence · Health · Environment · Water and treatment
Chemical properties of niobium
| Symbol / atomic number | Nb / 41 |
|---|---|
| Group / period / block | 5 / 5 / d |
| Standard atomic weight | 92.906 37(1) |
| Electron configuration | [Kr] 4d4 5s1 |
| Common oxidation state(s) | +5, +3 |
| Density (20 °C) | 8.57 g cm−3 |
| Melting point | 2477 °C |
| Boiling point | 4741 °C |
| Electronegativity (Pauling) | 1.60 |
| Non-bonded atomic radius | 0.218 nm |
| First ionisation energy | 652.13 kJ mol−1 |
| Representative isotopes | 93Nb (stable) |
| CAS registry number | 7440-03-1 |
Standard atomic weight follows CIAAW. Parentheses indicate uncertainty in the final quoted digits. Other physical and atomic data follow the Royal Society of Chemistry. Non-bonded atomic radii are method-dependent.
Niobium: properties, uses and occurrence
Niobium is used in steels, superalloys and superconducting materials, including magnets for medical imaging and scientific equipment. It occurs with tantalum in columbite and related ores. Natural niobium is essentially the single stable isotope 93Nb.
Health and safety
Niobium has no known biological role. Occupational risk depends on the specific compound and whether dust or fumes can be inhaled; evaluate exposure using the relevant safety data and workplace controls.
Niobium in the environment
Niobium is generally found in mineral forms rather than as free metal. Occurrence in water is expected to depend on source, compound, suspended solids and analytical method; avoid extrapolating environmental behavior from bulk-metal properties alone.
Niobium in water and treatment
Niobium is not a routine water-treatment parameter. For an industrial stream containing niobium, first define the target compound and whether the objective is removal or recovery. Measure both dissolved and total recoverable fractions with a method validated for the matrix, then use treatability tests to evaluate precipitation, adsorption or membrane options as appropriate; no single method is suitable for every stream.
Niobium page last reviewed: by Lenntech.
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