INVESTIGATION OF LIQUID PALLADIUM-TIN ALLOYS

The value of the heat of solution of palladium in liquid tin has been measured as a function of temperature and concentration in the dilute solution range and between 700 and 800°K. The partial heat of solution has been compared to the heats of formation of solid PdSn, PdSn2, and PdSn4. The similarity between the heat of solution and the heats of formation indicates that similar bonding may exist in all cases, and that each palladium atom in the liquid, like those in each of the compounds, is probably surrounded by four permanent tin neighbors. Density measurements of a 4% Pd liquid alloy show that a tetrahedral PdSn4 molecule would have a Pd-Sn distance very close to that found in the intermetallic compounds.