The molecule SiF4 (silicon tetrafluoride) is nonpolar.
To understand why, we need to consider the molecular geometry and the electronegativity of the atoms involved. Silicon (Si) is bonded to four fluorine (F) atoms. Fluorine is highly electronegative, meaning it pulls electron density toward itself. However, in SiF4, the geometry is tetrahedral. This symmetry means that the dipoles from each Si-F bond cancel each other out.
As a result, although the Si-F bonds are indeed polar due to the large difference in electronegativity between silicon and fluorine, the overall molecule does not have a net dipole moment because of its symmetrical shape. Therefore, SiF4 is classified as a nonpolar molecule.