THERMODYNAMICS OF BROMO-ADAMANTANE AND CARBON TETRABROMIDE UNDER PRESSURE

The phase behaviour of two bromo derivatives, carbon tetrabromide and bromo adamantane, exhibiting orientationally disordered phases, was st udied under pressure by thermobarometric analysis. Measurements perfor med under isochoric conditions allowed the study of transformations in volving plastic phases with high vapour pressures. The pressure - temp erature phase diagrams were determined. Pretransitional effects were o bserved near the plastic - liquid transition. Molar volume changes for both the solid to plastic and plastic to liquid first order phase tra nsitions, and the pressure coefficients - at constant volume - of the phases were determined.