Abstract :
Measurements of the electrical conductivity were performed in KHSO4 at pressures between 0.5 and 2.5 GPa and in the temperature range 120–350 °C by the use of the impedance spectroscopy. The temperatures of the α–β phase transition (TTr) and of the melting (Tm), determined from the Arrhenius plots ln(σT) vs. 1/T, increase with pressure up to 1.5 GPa having dT/dP∼+45 K/GPa. Above the pressure 1.5 GPa, the pressure dependencies of TTr and Tm are negative dT/dP∼−45 K/GPa. At pressures above 0.5 GPa, the reversible decomposition of KHSO4 into K3H(SO4)2+H2SO4 (and probably into K5H3(SO4)4+H2SO4) affects the electrical conductivity of KHSO4, with the typical values of the protonic electrical conductivity, c. 10−1 S/cm at 2.5 GPa.
