Periodic Table
77
Ir
192.22
Iridium
Transition Metal2nd densest; most corrosion resistant; Ir layer at K–Pg boundary.
Electronic Configuration
[Xe] 4f¹⁴ 5d⁷ 6s²or1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f¹⁴ 5d⁷ 6s²
Electron shells
2e⁻n=1
8e⁻n=2
18e⁻n=3
32e⁻n=4
15e⁻n=5
2e⁻n=6
Properties
Atomic number
77
Atomic mass
192.22 u
Category
Transition Metal
Block / Group / Period
d · 9 · 6
Valence electrons
2
Oxidation states
+3, +4
Electronegativity
2.2
Atomic radius
180 pm
Ionization energy
880 kJ/mol
Electron affinity
151 kJ/mol
Melting point
2719 K / 2446 °C
Boiling point
4701 K / 4428 °C
Density
22.56 g/cm³
State at 25 °C
solid
Personal Notes
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