Pressure Dependence of the Alpha-Beta Transition Temperature in Silver Selenide

The pressure dependence of the α-β transition temperature in Ag$_{2}$Se was determined by observing the temperature at which the sharp change in resistivity occurs when Ag$_{2}$Se is transformed from the low-temperature orthorhombic to the high temperature body-centered-cubic form. The transition temperature increased from 133 °C at 1 atmosphere to 298°C at 47 kilobars. The value of $\Delta $H$_{\text{t}}$, the heat of transformation, of 2.19 kcal/mol measured calorimetrically agreed well with the value calculated from dT/dP of the transition.