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 studied under pressure by thermobarometric analysis. Measurements performed under isochoric conditions allowed the study of transformations involving plastic phases with high vapour pressures. The pressure — temperature phase diagrams were determined. Pretransitional effects were observed near the plastic — liquid transition. Molar volume changes for both the solid to plastic and plastic to liquid first order phase transitions, and the pressure coefficients — at constant volume — of the phases were determined.