To assess the magnitude of aromatic stabilization in the tri-thorium ring, Lin and Mo used the simplified charged model cluster Th3 10+ derived from the Th3Cl6 4+ cage at its equilibrium geometry with the highest-occupied molecular orbital (HOMO) that visually resembles the corresponding 3c2e-type HOMO in the original (experimentally validated) model cluster by Boronski et al. The authors used a sophisticated computational method called the block-localized wavefunction at the density functional theory (BLW-DFT) to estimate aromatic stabilization in terms of the extra cyclic resonance energy (ECRE). The calculated ECRE value of 18.7 kcal mol -1 (Figure , Supporting Information) falls between the corresponding values for the archetypical σ-aromatic H3 + (31.9 kcal mol -1 ) and non-aromatic Li3 + (0.2 kcal mol -1 ), which prompted Lin and Mo to make the conclusion that the tri-thorium ring is considerably σ-aromatic; for comparison, the aromatic stabilization energy in thiophene is about 18.6 kcal mol -1 . Unfortunately, in additional to several potential issues associated with the very definition of ECRE (see Supporting Information), the conclusion about aromatic stabilization made for such extremely ionized model cluster as Th3 10+ may be not directly transferable to the tri-thorium ring in the isolated compound. This is because strict separation of charge between the Th3Cl6 cage and the surrounding ligands in the model crystalline actinide cluster dramatically affects the ECRE in the Th3 core. Lin and Mo, and Tomeček et al., made the charged model cluster Th3Cl6 4+ by removing two K cations (the spectators) and three cyclooctatetraenyl dianion ligands (COT 2-) from the original neutral model by Boronski et al. However, the covalent bond order between each thorium atom and the corresponding COT ligand is equal to 0.96, which means almost perfect sharing of the 7s 2 electrons (Th) with the 8π-subsystem (COT) rather than transfer of two electrons to make the aromatic 10π-electron COT 2- To the best of our knowledge, there is no reliable and universal method to quantitatively assess the effect of aromatic stabilization in all-metal clusters. However, in the case of the threecenter two-electron bonding the potentially extra stabilizing effect of PBC can be deduced from the molecular orbital energies in linear and cyclic isomers. This is because within the one-electron approximation the effect of the periodic boundary conditions on the 3c2e σ-bonding is directly proportional to the corresponding effect on the 3c2e orbital itself (Figure , SI). Accordingly, by comparison of the orbital energy levels of the equal-length linear asymmetric (C∞v) and cyclic symmetric (D3h) forms of the models Th3, Th3 4+ , and Th3 10+ , it can easily be found that only in the ionized clusters the D3h isomers (with cyclically delocalized charge) have the orbital energies lower than the C∞v isomers (with the electrons shared only by two Th atoms) (Figure ). This means that only the charged model clusters can be considered effectively stabilized by the PBC.