Atomic and nuclear properties of meitnerium (Mt)
Atomic number 109  
Atomic mass [278.1563(7)] g mole-1
Specific gravity ?? g cm-3
Mean excitation energy 1115.0 eV
Minimum ionization 1.090 MeV g-1cm2
Nuclear collision length 124.0 g cm-2
Nuclear interaction length 220.2 g cm-2
Pion collision length 146.6 g cm-2
Pion interaction length 246.0 g cm-2
Radiation length 5.26 g cm-2
Critical energy 6.02 MeV (for e-)
Molière radius 18.55 g cm-2
Plasma energy ωp 67.74 eV
Muon critical energy 112. 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 is no stable isotope, [atomic mass] is that of the longest-lived isotope known as of Jun 2017.
Note: Density 14.0 g/cm3 and Ieff = 1115 eV assumed in calculating critical energies and dE/dx.
Table of isotopes via WIKIPEDIA