ClF5 is a polar molecule. To understand why, we need to look at its molecular geometry and the electronegativity of the atoms involved.
Chlorine (Cl) is the central atom in ClF5, surrounded by five fluorine (F) atoms. Fluorine is more electronegative than chlorine, which means it attracts the bonding electrons more strongly. This creates a dipole moment where the positive end is closer to the chlorine atom and the negative end is towards the fluorine atoms.
The molecular geometry of ClF5 is square pyramidal. This means the molecules do not have a symmetric distribution of charge. While the polar bonds between Cl and F may counterbalance each other, the asymmetrical arrangement leads to an overall dipole moment in one direction.
Thus, ClF5 has a net dipole moment, indicating that it is polar.