New graphite intercalation compounds C4KO2 and C8KO2

New graphite intercalation compounds were obtained by intercalation of potassium superoxide KO2 into graphite in presence of potassium metal. Stage 1 (assigned formula C4KO2, Ic = 8.44 Å) and stage 2 (assigned formula C8KO2, Ic = 11.75 Å) compounds were isolated. Quadruple intercalate layer K-O-O-K is supposed. The results of magnetic susceptibility measurements suggest nonmagnetic states of oxygen species. Metal-like temperature dependence of c-axis resistivity was obtained in 1.5–300 K range where the resistivity values at room temperature are 0.07 Ωcm and 0.81 Ωcm for C4KO2 and C8KO2, respectively.