Impedance and admittance measurements at mildly polarizing potentials, using a static mercury electrode in aqueous alkali metal chlorides at neutral and alkaline pH, exhibit Mott-Schottky plots showing both p-type and n-type semiconduction depending on the frequency. There are also unique differences in the nature of complex plane plots and Bode plots for different alkali metal ions, and these provide clues to the ion-solvent interactions near the electrode surface. At sufficiently positive potentials Hg2CI2 and an electron are produced by a charge transfer reaction. The dual semiconduction behavior may be due to the unique disproportionation properties of the mercurous ion to produce different double layers. Formation of inner oxide and outer hydroxide passive layers has been suggested by others to explain the dulexsemiconducting behavior of Fe-18Cr alloy in neutral and acid solutions.
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