𝐸 / * and ∆𝐺 BC! can be correlated via the cation acidity, i.e., Z 2 /r, where Z and r are the charge and radius of cation, respectively . Values of cation acidity and ∆𝐺 BC! of cations employed in this work are linearly correlated based on the data from literature as shown in Fig. , which is consistent with a recent report by Koper and co-workers . The linear relation between the cation acidity and ∆𝐺 BC! based on linear fitting in Fig. is: