Atomic number 26
Iron
Transition metal
In the real world
Quick facts
- Atomic mass
- 55.845
- Group
- 8
- Period
- 4
- State (STP)
- solid
- Electronegativity
- 1.83
- Common ox. states
- +2, +3
Properties
Electron configuration
[Ar] 3d⁶ 4s²
- Ionization energy
- 762.5 kJ/mol
- Electron affinity
- 15.7 kJ/mol
- Melting point
- 1811.00 K (1537.8 °C)
- Boiling point
- 3134.00 K (2860.8 °C)
How dangerous is it?
1/5 · Low risk
Safe to hold as an ordinary metal, the same iron in nails and tools. The only caution is very fine iron powder, which can catch fire on its own.
- FlammableImmediate
Extremely fine iron powder can ignite in air without a spark because so much surface is exposed. (as a fine powder, not the solid metal)
The fine powder is kept sealed and away from air; ordinary iron objects need no special care.
How it bonds
Iron toggles between Fe²⁺ (ferrous, pale green in water) and Fe³⁺ (ferric, yellow-brown - rust). The Fe²⁺/Fe³⁺ couple is what lets hemoglobin pick up and release O₂. Rust is hydrated Fe₂O₃; iron always loses to oxygen given time.
Element Lore
Stories, history, and chemistry behind Iron.
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