Rhenium Ionization Energy

The Rhenium Ionization Energy is the energy required to remove from atom one mole of electrons with subsequent production of positively charged ion of Rhenium.
Re -> Re⁺ + e^-
This process can be repeated many times, but the energy cost is increased dramatically. The general equation for the Rhenium is:
Re^N+ -> Re^(N+1)+ + e^-

Re -> Re¹⁺ = 760 kJ/mol = 181.82 Kcal/mol
Re¹⁺ -> Re²⁺ = 1260 kJ/mol = 301.44 Kcal/mol
Re²⁺ -> Re³⁺ = 2510 kJ/mol = 600.48 Kcal/mol
Re³⁺ -> Re⁴⁺ = 3640 kJ/mol = 870.81 Kcal/mol
Re⁴⁺ -> Re⁵⁺ = 4900 kJ/mol = 1172.25 Kcal/mol
Re⁵⁺ -> Re⁶⁺ = 6300 kJ/mol = 1507.18 Kcal/mol
Re⁶⁺ -> Re⁷⁺ = 7600 kJ/mol = 1818.18 Kcal/mol