D.C. electrical conductivity, DTA and coulometric studies on (NH4)3 H(SO4)2 single crystals are made. Conductivity is markedly anisotropic with maximum along c∗ direction. A sudden jump in the conductivity plot along c∗ direction at 413 K is supported by a large endothermic peak in DTA, confirming the presence of transition at this temperature. The values of activation energy calculated from conductivity measurements indicated that the charge carriers are protons. This was further confirmed by coulometric experiment where the gas evolved was hydrogen, as established by a gas chromatograph and the volume of H2 released agreed with that expected from electrolysis. The mechanism of protonic conduction in this crystal is discussed.
