Second, Peerless et al. speculate that the isolated cluster 1 -is aromatic while the heterometallic cluster [{(cod)Ir}3Bi6] -(2 -) is not due to its lower symmetry. In particular, the authors consider that the more regular {Bi6} prism in 1 -is better described as the Bi6 2-(allegedly featuring φaromaticity) whereas that of more structurally distorted 2 -by the non-aromatic Bi6 4-. The authors should be aware, however, that symmetry cannot be used as an aromaticity criterion per se, and distorted aromatic systems are known to preserve their bonding patterns and aromatic character. In fact, the average Wiberg bond index (WBI) clearly shows that the covalent bonding Bi-Bi inside the prisms is almost the same in both clusters (Figure ). More specifically, the average WBI values for the annular (transannular) Bi-Bi bonds in 1 -and 2 -read 0.65 (0.32) and 0.61 (0.36), respectively, and therefore they do not differ significantly enough to justify differentiation of the clusters in terms of aromaticity. What really makes the cluster 1 -more symmetric is higher hapticity of the η 5 -Cp ligands (vs the η 4 -cod in 2 -) implying more d-orbitals involved in bonding, and, consequently, noticeably larger average WBI values for the bismuth-metal bonds (Figure ). It should also be noticed that the reported by the authors increase of WBI for the annular Bi-Bi bonds upon reduction from 0.99 (Bi6 with no π-electrons) to 1.10 (Bi6 2-) is too small to be interpreted as a sign of local π-aromaticity in the {Bi3} subunits. To put it into a context, the ΔWBI of 0.11 equals to the weak interaction between the formally non-bonded para-related carbon atoms in benzene, and is nowhere near the π-component of 0.44 for the π-aromatic cyclopropenyl cation.