Equilibrium Between Protonic Species and Conductivity Mechanism in Antimonic Acid, H2Sb4O11·nH2O.

Abstract Infrared spectroscopy, proton magnetic resonance, thermogravimetry and differential scanning calorimetry have been used to study antimonic acid of the general formula H 2 Sb 4 O 11 · n H 2 O at different temperatures and with different water contents. There are three types of protonic species, H 3 O + , H 2 O and OH, attached to the Sb 4 O 11 framework. The relative concentration of H 3 O + appears to increase at lower temperatures, being in equilibrium with the trapped protons of OH groups; quantitative 1 H NMR data derived from various models are given. The conductivity mechanism of this superionic protonic conductor is discussed.