A study was made of the structures of these materials. It was recalled that the charge carriers of protonic conductors were protons, and protonic entities such as OH-, H2O and [H(H2O)n]+. A small fraction of these compounds had exceptionally high proton conductivities. Heteropolyacids had conductivities of between 0.001 and 0.1S/cm at room temperature.

M.Davidovic, U.B.Mioc: Materials Science Forum, 1996, 214, 99-108