Magnetic anomalies of Na3C60 Original Research Article

Sodium fullerides Na3C60 have been synthesized by liquid phase reaction and investigated by X-ray diffraction (XRD), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) and differential thermal analysis (DTA). The crystal structure of synthesized Na3C60 is complicated and different from reported in the literature. About seven times increase of paramagnetic susceptibility with increasing temperature has been observed in Na3C60 fulleride at 240–260 K. In the same temperature range new line at about 255 ppm appears in the 23Na NMR spectrum indicating significant increase of electron density near Na nucleus. The observed effect can be explained by the formation of paramagnetic Na4+ clusters in the fulleride.