Iridium vs Platinum

Side-by-side comparison of Iridium (Ir, element 77) and Platinum (Pt, element 78) by atomic structure and physical properties.

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PropertyIr Iridium Pt Platinum
Atomic number7778
SymbolIrPt
NameIridiumPlatinum
Categorytransition-metaltransition-metal
Standard Atomic Weight192.217 u195.084 u
Period66
Group910
Blockdd
Phase at STPSolidSolid
Electron configuration[Xe]4f145d76s2[Xe]4f145d96s1
Oxidation states[-3, -2, -1, 1, 2, 3, 4, 5, 6, 7, 8, 9][-3, -2, -1, 0, 1, 2, 3, 4, 5, 6]
Electronegativity (Pauling)2.22.28
Electron affinity1.565 eV2.1228 eV
Density2.25622e+4 kg/m³2.146e+4 kg/m³
Melting point2445.85 °C1768.4 °C
Boiling point4427.85 °C3824.85 °C
Discovery year18031735

Key Differences

PropertyIr IridiumPt Platinum
Standard Atomic Weight192.217 u ↓ lower195.084 u ↑ higher
Density2.25622e+4 kg/m³ ↑ higher2.146e+4 kg/m³ ↓ lower
Melting point2445.85 °C ↑ higher1768.4 °C ↓ lower
Boiling point4427.85 °C ↑ higher3824.85 °C ↓ lower
Electronegativity (Pauling)2.2 ↓ lower2.28 ↑ higher
Electron affinity1.565 eV ↓ lower2.1228 eV ↑ higher
Group9 10
Electron configuration[Xe]4f145d76s2 [Xe]4f145d96s1
Discovery year1803 1735