Next, we located another interesting case where the C6 coefficient changes sharply when CN transitions from 2.5 to 3.5: the Hf atom. Although Hf is not suitable for observing the artifact in the Kuratowski-type cluster environment (since the step occurs at CN ≈ 2.8 and in a Kuratowski-type cluster, the metal already has a coordination number of 3) we decided to consider an Hf complex with only two nitrogen-containing ligands. Indeed, we found two minima: [H2-Hf(NH2)2] --( ) and [H2-Hf(NH2)2] --(2), shown in Figure .