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The study of potassium-oxygen and cesium-oxygen graphite intercalation compounds (GICs) first synthesized by the authors is presented. It is shown that these GICs are formed in reactions of graphite with alkali metal/alkali Superoxide mixtures or with alkali suboxide (in the case of cesium). Stage 1 and 2 potassium-oxygen GICs Jmterplanar distance 8.44 A), and stages 1, 2 and 5 cesium-oxygen GICs (interplanar distance 9.84 A) were isolated. X-ray diffraction, XPS, TEM electron diffraction and chemical analysis were used to characterize the content and constitution of the GICs synthesized. Metal-like temperature dependence of c -axis resistivity was obtained in the 1.5–300 K range where the resistivity values at room temperature are 0.07, 0.81, 2.6 and 0.089 Ωcm for KO stagel, KO stage 2, CsO stage 1 and CsO stage 2 compounds, respectively. All the GICs exhibit low spin susceptibility (order of 10 −7 emu/g) which suggests the absence of magnetic species O 2 − .

We have observed angular dependent magnetoresistance oscillations (ADMRO) in the out-of-plane resistivity of low-stage SbCl 5 -intercalated graphite. This new phenomenon is a semi-classical geometric resonance effect inherent in quasi two-dimensional systems whose Fermi surface is weakly corrugated in the k z -direction. Typically, ADMRO is characterized by peak positions that are periodic in tan θ. The peaks in ϱ zz occur when the average of the k z -component of electron group velocity around its extended orbit is zero. Significant deviations from ‘standard’ behaviour are found. The implications for electronic structure are discussed.