Melting entropies and molar specific heats of some intermetallic phases of tellurium

In order to get information about the thermodynamic properties of tellurium alloys which have some importance in semiconductor technology, the formation enthalpies and the molar specific heats of intermetallic compounds in some selected systems have been determined. The determination of the formation enthalpies has been carried out using calorimetrically measured melting enthalpies of suitable alloys and the mixing enthalpies of the corresponding alloy melts. The molar specific heats have been measured with the aid of a scanning calorimeter. A consideration of the factors which can influence alloy formation shows that the amount of the formation enthalpies of the investigated compounds is mainly determined by the difference of the electronegativities of the components. Regarding the specific molar heats of the investigated compounds, negative deviations from the Neumann-Kopp rule have been observed. These deviations are bigger, the bigger the differences of the electronegativities are. This leads towards corresponding negative, contributions to the formation entropies of the compounds. (orig.)