ISOLATION OF FULLERIDE PHASES BY DISTILLATION

A technique for the synthesis of phase pure alkali-metal fullerides is demonstrated. The fulleride compounds are distilled from mixed phase samples or from other pure phases by the preferential evaporation of e ither fullerenes or alkali-metal atoms. Distillation has been used to form K3C60, K4C60, RbC60, and Rb4C60 which exhibit core level photoemi ssion spectra that are consistent with bulk structure measurements. Th e KxC70 system, for which structural information has not been reported , was also examined and the compounds KC70, K3C70, and K4C70 were foun d.