Question

Which is more covalent LiF or LiI and why?

Answer 1

According to Fajan’s rule “with an increase in size of anion, the covalent character in a molecule increases”. With the increase in size of the anion the electron cloud density shifted to center, thus increases the covalent character. In LiI the anion 'I' has bigger size compared anion 'F' in LiF, therefore LiI is more covalent than LiF.