Niobium
transition metal · period 5 · group 5 · d-block
Niobium, also known as columbium, is a chemical element with the symbol Nb (formerly Cb) and atomic number 41. Niobium is a light grey, crystalline, and ductile transition metal.
What the numbers say
At standard temperature and pressure Niobium is a solid, sitting in period 5, group 5 of the d-block.
Its melting point of 2750 K (2477 °C) is the 7th highest of the 110 elements with a measured value — one of the most refractory elements there is.
At 8.57 g/cm³ it is the 38th densest of 96 elements with a quoted density.
Pauling electronegativity is 1.6. Paired with oxygen (3.44) that is a difference of 1.84, which puts the bond predominantly ionic — expect a stable oxide ceramic.
In the solid state it takes a body-centered cubic structure — BCC packing is stronger but shows a ductile-to-brittle transition as temperature drops.
It is reported in 5 oxidation states (-1, 2, 3, 4, 5), which sets how many distinct compounds and phases it can form.
First identified in 1801.
Crystal structure
Solid Niobium adopts a Body-centered Cubic arrangement, in the Cubic (isometric) system — axes a = b = c, angles α = β = γ = 90°. Symmetry controls the anisotropy of stiffness and thermal expansion, and the available slip systems set how far the metal deforms before it fractures.
Check it against computed structures
The structure search queries the Materials Project, OQMD and the Open Materials Database for computed crystal structures containing Nb — with DFT formation energy, hull stability and band gap where the provider publishes them.
K 2 · L 8 · M 18 · N 12 · O 1
Properties
| Atomic number | 41 |
|---|---|
| Atomic mass | 92.906372 u |
| Series | transition metal |
| Group | 5 |
| Period | 5 |
| Block | d-block |
| Phase at STP | Solid |
| Density | 8.57 g/cm³ |
| Melting point | 2750 K (2477 °C) |
| Boiling point | 5017 K (4744 °C) |
| Electronegativity (Pauling) | 1.6 |
| Electron configuration | [Kr] 4d⁴ 5s¹ |
| Crystal structure | Body-centered Cubic |
| Oxidation states | -1,2,3,4,5 |
| Discovered | 1801 |
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See Nb in context with all 118 elements.
Working with niobium in a real design?
Ask the materials chat how Nb behaves in your alloy system, what it does to weldability, and which grades to look at — with the source of every number named.