Thermodynamic properties of the graphite-bisulfate lamellar compounds

An electrochemical technique has been utilized to obtain thermodynamic information on the graphite-bisulfate lamellar compounds. The compounds C24+·HSO4−· 2.5H2SO4, C48+·HSO4−·2.5H2SO4 and C72+·HSO4−·2.5H2SO4 were prepared by electrolysis of graphite in sulfuric acid. Emf measurements were made at temperatures of 35–65°C on cells of the type Hg, Hg2SO4/|H2SO4(conc)/| equilibrium mixture of bisulfate compounds. Free energies, enthalpies and entropies of formation of the compounds were determined. The nature of the chemical bonding in the compounds is discussed.