Lanthanide Ionization Energies and the Sub-Shell Break. Part 2. The Third and Fourth Ionization Energies

摘要

By interpolating a 4f6s → 4f7s transition within the sequence f → f rather than between f and f, revised third and fourth ionization energies of the lanthanides have been obtained. The revised values, together with the second ionization energies calculated in a previous paper, are used to calculate values of the standard enthalpies of formation of the gaseous tripositive ions, ΔH(M,g), and of the lattice and hydration enthalpies of some lanthanide compounds and ions in the trivalent and tetravalent states. The displacements of f values from nearly smooth f → f variations exceed 30 kJ mol and indicate substantial subshell breaks.