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.