Gadolinium Ionization Energy

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

Gd -> Gd¹⁺ = 592.5 kJ/mol = 141.75 Kcal/mol
Gd¹⁺ -> Gd²⁺ = 1167 kJ/mol = 279.19 Kcal/mol
Gd²⁺ -> Gd³⁺ = 1990 kJ/mol = 476.08 Kcal/mol
Gd³⁺ -> Gd⁴⁺ = 4250 kJ/mol = 1016.75 Kcal/mol