Polymeric sheets in Mg4C60

We present preliminary results on the preparation and structure of Mg4C60, a new fulleride polymer. A series of MgxC60 compositions (0<x<6) were prepared by solid state reaction. While most samples were multiphase, a single phase material was obtained at the nominal composition Mg4C60. The X-ray diffraction pattern of Mg4C60 was successfully indexed and fitted to a rhombohedral structure based on two-dimensional polymeric sheets of C60 ions. This result extends the family of fulleride polymers to the salts of multiply charged cations and thus opens a new direction in this field.