Surface tensions of basic NaCl-AlCl3, and LiCl-AlCl3 binary melts

Surface tensions of basic NaCl-AlCl3 and LiCl-AlCl3 binary melts were measu red by using capillary-rise method up to 1200 Ii precisely. It was found th at the adding very small amount of AlCl3 into NaCl or LiCl decreases the su rface tension very steeply to less than half value of NaCl or LiCl. The sur face enthalpy and surface entropy also decreases steeply. These phenomena a re similar to the action by surface active agent although the phenomena are rare in molten salt systems. This is due to the formation of the compound of NaAlCl4 and LiAlCl4. The compound is considered to be concentrated in su rface phase due to their lower coulombic energy, and resulted the decrease of surface tension and surface energy, and furthermore the increase of orde ring on surface phase. Based on present results and the thermodynamic consi deration, the concentrations of NaAlCl4 and LiAlCl4 in the surface phase we re calculated.