Fullerite intercalated with argon at room temperature: Synthesis and physicochemical properties

Fullerite with the bulk formula ArxC60, where 0.60 < x < 0.75, was synthesized by precipitation from a mixture of argon-saturated solutions. The fcc unit cell parameter in the sample was 1.422 nm; the orientational phase transition (OPT) temperature was 247 K. These values noticeably differ from the relevant parameters of undoped fullerite (1.416 nm and 260 K, respectively). Heating accompanied by argon evolution restores the fullerite C60 structure.