PbI2 (lead(II) iodide) is a non-polar molecule.
To determine if a molecule is polar or non-polar, we need to consider the molecular geometry and the polarity of the individual bonds within the molecule. PbI2 has a linear molecular geometry, with the lead atom (Pb) in the center and two iodine atoms (I) on either side.
Each Pb-I bond is a polar covalent bond because iodine is more electronegative than lead. However, due to the symmetrical arrangement of the iodine atoms around the central lead atom and the linear molecular geometry, the polarities of the individual Pb-I bonds cancel each other out. As a result, the net dipole moment of the molecule is zero, making PbI2 a non-polar molecule.
It's important to note that even though PbI2 is non-polar, the individual Pb-I bonds within the molecule are polar. The cancellation of the dipole moments is a result of the symmetrical arrangement of the polar bonds in the molecule.