Effect of Ion Sizes on Salt Melting Points

The dominant force in ionic liquids is Coulombic attraction between ions. The Coulombic attrachon term is given by Equation (3.1-2)  

This can be illustrated for a series of sodium salts, shown in Table 3.1-1, in which the size of the anion is varied. 

The overall lattice energies of ionic solids, as treated by the Born-Eande or Kaputin-sldi equations, thus depends on (i) the product of the net ion charges, (ii) ion-ion separation, and (iii) pacldng efficiency of the ions (reflected in the Madelung constant, M, in the Coulombic energy term). Thus, low-melting salts should be most 

This can be illustrated for a series of sodium salts, shown in Table 3.1-1, in which the size of the anion is varied. As the size of the anion is increased, the melting point of the salt decreases, reflecting the weaker Coulombic interactions in the crystal lattice. On increasing the thermochemical radius of the anion, from to 

---