Iodine oxide pentafluoride (IOF5) is polar as the unequal dipole moments of polar I=O and I-F bonds do not get canceled equally in the asymmetrical octahedral shape of the molecule.
IOF5 consists of one I=O bond and five I-F bonds.
Each I=O bond is polar as it consists of an electronegativity difference of 0.78 units between the double covalently bonded iodine (E.N = 2.66) and oxygen (E.N = 3.44) atoms.
In contrast, the electronegative difference in each I-F bond is even higher i.e., 1.32 units between the single covalently bonded iodine and fluorine (E.N = 3.98) atoms.
Fluorine being the most electronegative element of the Periodic Table, strongly attracts the shared electron cloud from each I-F bond towards itself.
In IOF5, the central I-atom gains a partial positive (δ+) charge, while the more electronegative O and F-atoms gain strong partial negative (δ–) charges.
There is no lone pair of electrons present on the central halogen (iodine) atom; thus, the molecule possesses an octahedral shape and molecular geometry identical to its ideal electron pair geometry.
The sideways directing, I-F dipole moments get canceled equally in this octahedral shape, but the higher downwards-pointing I-F dipole moment does not get canceled with the oppositely directed, smaller I=O dipole moment.
The charged electron cloud stays non-uniformly distributed. Thus, IOF5 is overall polar (net µ> 0).
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