Atomic and nuclear properties of roentgenium (Rg)

Quantity	Value	Units
Atomic number	111
Atomic mass	[282.1691(7)]	g mole-1
Specific gravity	??	g cm-3
Mean excitation energy	1143.0	eV
Minimum ionization	1.091	MeV g-1cm2
Nuclear collision length	124.5	g cm-2
Nuclear interaction length	221.2	g cm-2
Pion collision length	147.1	g cm-2
Pion interaction length	247.1	g cm-2
Radiation length	5.18	g cm-2
Critical energy	5.93	MeV (for e-)
Molière radius	18.54	g cm-2
Plasma energy ℏωp	67.87	eV
Muon critical energy	111.	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
Note: Since there are no stable isotopes, [atomic mass] is that of the longest-lived isotope known as of Jun 2017.
Note: Density 14.0 g/cm³ and I_eff = 1143 eV assumed in calculating critical energies and dE/dx.
Table of isotopes via WIKIPEDIA