The paper reports computations for all lanthanoids L on their encapsulation into the only C74 IPR (isolated pentagon rule) cage (L@C74), for Z@C82 based on encapsulation into the IPR C2v C82 cage, and also for the mixed (metal-sulfur) Z2S@C82 endohedrals. Their structural and energetic characteristics are used for evaluations of the relative production yields, employing the encapsulation Gibbs-energy terms and saturated metal pressures.
It is moreover shown that the encapsulation potential-energy changes in such series can be well related to the mere ionization potentials of the free metal atoms.