The melting point of AlF3 is 104°C and that of SiF4 is -77°C (it sublimes) because : — Chemical Bonding Chemistry Question

💡 Solution & Explanation

Step 1: According to Fajan's rules, the covalent character in an ionic bond is favored by factors that increase the polarization of the anion by the cation. Step 2: High polarization is facilitated by a small cation size (high polarizing power), a large anion size (high polarizability), and high charges on both the cation and the anion. Step 3: Since all of these factors favor covalency, the correct option is (d).