Synthesis and physical properties of MgxC70

New C70 fullerides with compositions of MgxC70 at 1 < x ≤ 5 were prepared by solid state reaction. While most samples with 1 < x < 4 were multiphase, a single phase was obtained at x = 5 . Mg5C70 was found to be a Mg-saturated phase and its x-ray diffraction profile was successfully assigned to a simple orthorhombic structure with a = 1.684 , b = 1.462 , and c = 1.384 nm . Mg5C70 was found to be non-metallic and exhibited an anomaly in magnetic susceptibility at approximately 80 K. No superconducting transition was found for MgxC70 ( 1 < x ≤ 5 ) down to a temperature of 2 K.