Viscosity of AlCl3-LiCl-NaCl acidic ternary melt

Viscosities of LiCl-50 similar to 75mol%AlCl3, NaCl-50 similar to 75mol%AlCl3 and LiCl-NaCl-50mol%AlCl3 melts have been measured by using a capillary viscometer in which the melts were sealed perfectly. The viscosities were determined by calculating the melt composition which were varied by changing temperature due to the high vapor pressure of the melts. The viscosity shows maximum at the composition corresponding to the formation of dimeric Al2C7- complex anion. The maximum was sharper in NaCl-AlCl3 than in LiCI-AlCl3, although LiCl-AlCl3 showed generally higher viscosity, and decreased with increasing temperature in both systems. These phenomena accord with the results of thermodynamic studies in the stability of complex anions.