Low‐Temperature Heat Capacities and Thermodynamic Functions of Some Platinum and Palladium Group Chalcogenides. I. Monochalcogenides; PtS, PtTe, and PdTe

Abstract

Heat capacities of platinum monosulfide, platinum monotelluride, and palladium monotelluride were measured in the range 5–350°K. They show the normal sigmoidal temperature dependence with no evidence of transitions or other anomalies. The derived heat‐capacity equations were integrated. Values of heat capacities, entropy and enthalpy increments, and of the free‐energy function are tabulated for selected temperatures. At 298.15°K, the third‐law entropies are 13.16 cal gfw—1 °K—1 for PtS, 19.41 cal gfw—1 °K—1 for PtTe, and 21.42 cal gfw—1 °K—1for PdTe. The new data on PtS have been correlated with existing decomposition‐pressure data to evaluate ΔHf, ΔFf, and ΔSf298.15°K. Entropies for other platinum‐metal monochalcogenides were estimated.