Atomic and nuclear properties of materials:
Radon (Rn)

Quantity	Value	Units	Value	Units
Atomic number	86
Atomic mass	[222.0176]	g mole-1
Specific gravity (20° C, 1 atm)	9.07E-03	g cm-3
Minimum ionization	1.116	MeV g-1cm2	1.011E-02	MeV cm-1
Nuclear collision length	116.3	g cm-2	1.283E+04	cm
Nuclear interaction length	204.3	g cm-2	2.253E+04	cm
Radiation length	6.28	g cm-2	693.2	cm
Critical energy	7.71	MeV (for e-)	7.43	MeV (for e+)
Molière radius	17.30	g cm-2	1908.	cm
Plasma energy	1.71	eV
Muon critical energy	160.	GeV
Melting point	202.1	K	-71.00	C
Boiling point @ 1 atm	211.4	K	-61.70	C

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
Note: Since there is no stable isotope, given atomic mass is that of the longest-lived known isotope as of Jan 2007.
Table of isotopes
x ray mass attenuation coefficients