Iron vs Cobalt

Side-by-side comparison of Iron (Fe, element 26) and Cobalt (Co, element 27) by atomic structure and physical properties.

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PropertyFe Iron Co Cobalt
Atomic number2627
SymbolFeCo
NameIronCobalt
Categorytransition-metaltransition-metal
Standard Atomic Weight55.845 u58.933194 u
Period44
Group89
Blockdd
Phase at STPSolidSolid
Electron configuration[Ar]3d64s2[Ar]3d74s2
Oxidation states[-4, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7][-3, -1, 0, 1, 2, 3, 4, 5]
Electronegativity (Pauling)1.831.88
Electron affinity0.153236 eV0.661 eV
Density7874 kg/m³8860 kg/m³
Melting point1537.85 °C1494.85 °C
Boiling point2860.85 °C2926.85 °C
Discovery yearN/A1735

Key Differences

PropertyFe IronCo Cobalt
Standard Atomic Weight55.845 u ↓ lower58.933194 u ↑ higher
Density7874 kg/m³ ↓ lower8860 kg/m³ ↑ higher
Melting point1537.85 °C ↑ higher1494.85 °C ↓ lower
Boiling point2860.85 °C ↓ lower2926.85 °C ↑ higher
Electronegativity (Pauling)1.83 ↓ lower1.88 ↑ higher
Electron affinity0.153236 eV ↓ lower0.661 eV ↑ higher
Group8 9
Electron configuration[Ar]3d64s2 [Ar]3d74s2