Some hydration structures are quite large: the magic ion number structure (called "magic" because of its increased stability with respect to hydration structures involving a comparable number of water molecules – this is a similar usage of the word "magic" as in nuclear physics) might place the hydronium inside a dodecahedral cage. However, more recent ab initio method molecular dynamics simulations have shown that, on average, the hydrated proton resides on the surface of the cluster. Further, several disparate features of these simulations agree with their experimental counterparts suggesting an alternative interpretation of the experimental results.