CALORIMETRIC MEASUREMENTS OF THE ENTHALPIES OF FORMATION AND OF MIXING OF II VI AND III/V COMPOUNDS/

A Calvet microcalorimeter capable of operating to 1000 degrees C has b een used with liquid metal solution techniques to measure the mixing e nthalpies of InSb-GaSb, InSb-InAs, InAs-GaAs and CdTe-HgTe. In additio n enthalpies of formation are reported for CdTe (-100830+/-700 J/mol) and HgTe (-43600+/-590 J/mol). During the work a novel method of stirr ing based on gentle pumping induced by a cyclic variation in pressure has been introduced with computer-based data logging. The results of t his study have been used together with phase diagram and vapour pressu re data to produce thermodynamic descriptions of the ternary phase dia grams which are in good agreement with experiment.