Contrariwise, in the neutral model Th3 the corresponding 3c2e orbital in the cyclic isomer clearly makes no profits from the PBC as it has exactly the same orbital energy as its linear asymmetric counterpart (with more localized charge). It should be noted that the energy differences between isomers C∞v and D3h (0.00 eV, -3.68 eV, and -11.37 eV) correlate linearly (R 2 = 0.993) with the corresponding total charges of the model tri-thorium clusters (0, +4, +10), while the lack of such correlation is observed for the orbital energy differences between isomers D∞h and D3h. This is a direct manifestation of the foregoing incompatibility of these isomers (in the context of the PBC effect) due to different total lengths, L. Nevertheless, the fact that the C∞v isomer has lower orbital energy than the contracted D∞h one (with more extended charge delocalization) clearly shows that the atomic orbitals 6d are rather reluctant to σ-conjugation at this distance. This, in turn, is in full agreement with the conclusions from our previous study based on the analysis of the topological characteristics of the electron density. It should be noted that at distance shorter than the experimental one (RTh-Th=3.991 Å) the overlapping of 6d orbitals in the neutral tri-thorium ring may be much more effective, and weak but noticeable σ-aromatic stabilization could be theoretically possible (Figure ). However, one must realize that even a small contraction of Th-Th bonds in the crystalline actinide cluster implies size reduction of the entire Th3Cl6 cage, and consequently the enhancement of the Pauli repulsion between lone pairs of chlorine atoms crowed in the relatively small volume. This has been argued to have a negative impact on the thermodynamic stability of the complex. Therefore, the strong multicenter charge-shift bonding in the Th3Cl6 cage seems to enlarge the ring of weakly bonded thorium atoms inside to the extent that prevents any extra cyclic stabilization. This puts into question the core-shell syngenetic model of aromaticity proposed by Lin and Mo.