Formation of giant solvation shells around fulleride anions in liquid ammonia.

Here, we measure the solvation structure of fulleride C605- anions in potassium ammonia solution using neutron diffraction. We find a very strong solvation structure consisting of two shells of ammonia densely packed around the anion. The system's structure is driven by the propensity of ammonia molecules to direct one of their hydrogen bonds to the center of the anion while retaining axial hydrogen bonding within the shells. This permits high concentrations of solvent separated fulleride anions.