Atomic and nuclear properties of iridium (Ir)
QuantityValueUnits ValueUnits
Atomic number 77     
Atomic mass 192.217(3) g mole-1   
Specific gravity 22.42 g cm-3   
Mean excitation energy 757.0 eV   
Minimum ionization 1.134 MeV g-1cm2 25.42 MeV cm-1
Nuclear collision length 111.7 g cm-2 4.983 cm
Nuclear interaction length 194.8 g cm-2 8.687 cm
Pion collision length 135.1 g cm-2 6.027 cm
Pion interaction length 221.4 g cm-2 9.877 cm
Radiation length 6.59 g cm-2 0.2941 cm
Critical energy 7.67 MeV (for e-) 7.39 MeV (for e+)
Molière radius 18.24 g cm-2 0.8136 cm
Plasma energy ωp 86.36 eV   
Muon critical energy 145. GeV   
For muons, dE/dx = a(E) + b(E) E. Tables of b(E): PDF TEXT
Table of muon dE/dx and Range: PDF TEXT
Explanation of some entries
Table of isotopes Warning: may not be current
x ray mass attenuation coefficients