Niobium

Symbol: Nb
Atomic number: 41
Category: transition metals
Group: 5
Period: 5
Block: d
Atomic weight: 92.90638 g/mol
Electrons per shell: 2, 8, 18, 12, 1
CAS number: 7440-03-1
Phase: solid
Density: 8.57 kg/dm³ (near room temperature)
Melting point: 2750 K (2477 °C, 4491 °F)
Boiling point: 5017 K (4744 °C, 8571 °F)
Crystal structure: cubic body centered
Oxidation states: 5, 4, 3, 2
Electronegativity: 1.6 (Pauling scale)
Name's origin: Niobe
Name's meaning: the goddess of tears in Greek mythology
Facts:
- begins to oxidize in air at 200 °C
- a few commercial producers still like to refer to it as columbium
- is a shiny, white, soft, and ductile metal, and takes on a bluish tinge when exposed to air at room temperatures for a long time