Atomic and nuclear properties of materials:
Methane (CH₄)

Quantity	Value	Units	Value	Units
<Z/A>	0.62334
Specific gravity (20° C, 1 atm)	6.67E-04	g cm-3
Minimum ionization	2.417	MeV g-1cm2	1.613E-03	MeV cm-1
Nuclear collision length	54.0	g cm-2	8.096E+04	cm
Nuclear interaction length	73.8	g cm-2	1.106E+05	cm
Radiation length	46.47	g cm-2	6.965E+04	cm
Critical energy	146.86	MeV (for e-)	143.82	MeV (for e+)
Molière radius	6.71	g cm-2	1.006E+04	cm
Plasma energy	0.59	eV
Muon critical energy	1716.	GeV
Melting point	90.68	K	-182.5	C
Boiling point @ 1 atm	111.7	K	-161.5	C
Index of refraction (@ STP, Na D)	444.	(n-1)x106

Composition:

Elem	Z	Atomic frac*	Mass frac*
H	1	4.00	0.251306
C	6	1.00	0.748694
* calculated from mass fraction data.

Explanation of some entries
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