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Information valid for Ir-192 unless otherwise noted

Basic Information

Symbol: Ir
Atomic Number: 77
Mass: 192.217
Melting Point: 2410.0 C
Boiling Point: 4527.0 C
Number of Protons/Electrons: 77
Number of Neutrons: 115
Classification: Transition Metal
Crystal Structure: Cubic
Density @ 293 K: 22.5 g/cm3
Color: white

Atomic Structure

[Bohr Model of Iridium]
Number of Energy Levels: 6

  1. First Energy Level: 2
    Second Energy Level: 8
    Third Energy Level: 18
    Fourth Energy Level: 32
    Fifth Energy Level: 15
    Sixth Energy Level: 2


Isotope Half Life
Ir-188 1.7 days
Ir-189 13.2 days
Ir-190 11.8 days
Ir-190m 1.2 hours
Ir-190m2 3.2 hours
Ir-191 Stable
Ir-192 73.8 days
Ir-193 Stable
Ir-193m 10.5 days
Ir-194 19.3 hours
Ir-194m 170.0 days


Date of Discovery: 1804
Discoverer: S. Tenant
Name Origin: From the Latin word iridis (rainbow)
Uses: tip gold pens, crucible and special containers
Obtained From: gravel deposits with platinum