Synthesis and Stability of Actinium-225 Endohedral Fullerenes, Ac@C.

We report the first synthesis of Ac ( = 10 days) endohedral fullerenes,Ac@C. The Ac@C was produced with a 12 ± 2% efficiency by applying an electrical arc discharge between a source of α-particle emitter Ac (∼1 mCi, electroplated on a Pt disk) and a thin coat of "preformed" C on an Al disk (C thickness of ∼0.25 mg/cm).