Niobium (Nb)
Niobium is element 41, a transition metal in period 5, group 5 of the periodic table. At room temperature it is a solid.
Electron configuration [Kr] 4d4 5s1
Electrons per shell 2, 8, 18, 12, 1
Niobium data
| Atomic number | 41 |
|---|---|
| Symbol | Nb |
| Atomic mass | 92.906 u |
| Category | Transition metal |
| Group | 5 |
| Period | 5 |
| Block | d |
| State at 25 °C | solid |
| Melting point | 2750 K (2476.9 °C) |
| Boiling point | 5017 K (4743.9 °C) |
| Density | 8.57 g/cm³ |
| Electronegativity (Pauling) | 1.6 |
| Atomic radius | 137 pm |
| 1st ionization energy | 652 kJ/mol |
| Electron affinity | -86 kJ/mol |
| Oxidation states | -1, +2, +3, +4, +5 |
| Common ion charge | 5+ |
| Discovered | 1801 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through niobium’s configuration and its ions →
Where niobium sits
Niobium belongs to the transition metals. Its Pauling electronegativity of 1.6 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Niobium FAQ
What is the electron configuration of niobium?
Niobium (Z = 41) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d4 5s1. In noble-gas shorthand that is [Kr] 4d4 5s1. This is an exception to the simple Aufbau prediction (1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d3 5s2); a half-filled or filled subshell lowers the energy.
How many valence electrons does niobium have?
5 (1 outer s + 4 d electrons; 1 in the outermost shell).
What is the atomic mass of niobium?
The standard atomic weight of niobium is 92.906 u, so one mole weighs 92.906 g.
Is niobium a metal?
Yes. Niobium is a transition metal.
What is the charge of a niobium ion?
Niobium most commonly forms Nb5+.