Proton conductivity of simple ionic hydroxides - Part III : Band Model for the Proton Conductivity in AI(OH)3, Mg(OH)2 and Ca(OH)2

Two distinctly different proton conductivity mechanisms can be formulated for the simple ionic hydroxides using the optically derived proton lattice potential and the fact that a proton conduction band exists above the series of discrete energy levels which are due to the higher states of the O—H stretching mode. One mechanism is p-type and relies upon excess protons thermally excited to the lower edge of the proton conduction band. The other is n-type and involves defect proton mobility on some of the discrete intermediate energy levels.The protonic band gap appears to be a characteristic value for each hydroxide related to acidity.