041Transition metal · Group 5 · Period 5
Niobium
Niobium (Nb) is element 41, a transition metal in the d-block — group 5, period 5. It is a solid at room temperature with 5 electron shells (2, 8, 18, 12, 1) and an atomic mass of 92.906372 u.
- Atomic mass
- 92.91 u
- Phase · STP
- solid
- Melting
- 2750 K · 2477 °C
- Boiling
- 5017 K · 4744 °C
- Electronegativity
- 1.6
- Density
- 8.57 g/cm³
Photograph — Mauro Cateb, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
Identity
- Atomic number
- 41
- Standard atomic weight
- 92.91 u
- Category
- Transition metal
- Group
- 5
- Period
- 5
- Block
- d-block
- Oxidation states
- +5, +3
Physical properties
- Melting point
- 2750 K · 2477 °C
- Boiling point
- 5017 K · 4744 °C
- Density
- 8.57 g/cm³
- Molar heat capacity
- 24.6 J/(mol·K)
- Atomic radius
- 207 pm
- Electron affinity
- 88.516 kJ/mol
Atomic structure
41protons
52neutrons
41electrons
1valence e⁻
- Noble-gas notation
- [Kr] 4d4 5s1
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 4d4
- Electrons per shell
- 2, 8, 18, 12, 1
Periodic trends
Where Niobium ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
652.11
1.4k2
2.4k3
3.7k4
4.9k5
9.8k6
12.1k7
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- 1801
- Discovered by
- Charles Hatchett
- Named by
- —
- Appearance
- gray metallic, bluish when oxidized