Atomic and nuclear properties of materials:
Iridium (Ir)

Quantity	Value	Units	Value	Units
Atomic number	77
Atomic mass	192.217(3)	g mole-1
Density	22.4	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	86.36	eV
Muon critical energy	145.	GeV

For muons, dE/dx = a(E) + b(E) E. Tables of b(E): PS PDF TEXT
Table of muon dE/dx and Range: PS PDF TEXT
Explanation of some entries
Table of isotopes Warning: may not be current
x ray mass attenuation coefficients