Preparation and enrichment of samarium endohedral fullerenes

A graphite anode packed with a powder mixture of Sm 2 Co 17 , SiC, and graphite with a high atomic ratio of Sm/C was vaporized by direct current arc discharge under improved conditions including high helium pressure, low electric current, and wide electrode gap. The soot produced was successively extracted by CS 2 and pyridine, and the extracts were processed through column chromatography on silica gel. Matrix-assisted laser desorption-ionization time-of-flight (MALD-TOF) mass spectrometry analysis indicated that a high yield of samarium endohedral fullerenes (Sm@C 2n ) with Sm@C 84 as the most abundant one was achieved. Possible reasons leading to this high yield are discussed.