Why are pentahalides more covalent than trihalides?
Or
Account for the following.
$PC{{l}{5}}$ is more covalent than
$PC{{l}{3}}$
Higher the positive oxidation state of central atom, more will be its polarising power, which in turn, increases the covalent character of the bond formed between the central atom and the halogen atom. In pentahalides, the central atom is in + 5 oxidation state while in trihalides, it is in +3 oxidation state.Therefore, pentahalides are more covalent than trihalides.