Why is CF4 a non polar molecule, even though it contains polar bonds?
The Correct Answer and Explanation is:
Why is CF₄ a nonpolar molecule, even though it contains polar bonds?
CF₄ (carbon tetrafluoride) is a nonpolar molecule because of its symmetrical tetrahedral geometry, which causes the individual bond dipoles to cancel each other out, resulting in no overall molecular dipole moment.
Explanation :
Carbon tetrafluoride (CF₄) consists of a central carbon atom bonded to four fluorine atoms. Each C–F bond is polar due to the significant difference in electronegativity between carbon and fluorine. Fluorine, being more electronegative, attracts the shared electrons more strongly, creating a partial negative charge (δ–) on the fluorine atoms and a partial positive charge (δ+) on the carbon atom. This leads to the formation of four polar covalent bonds within the molecule.
Despite the polarity of the individual bonds, the overall molecule is nonpolar. This is due to the tetrahedral shape of CF₄, which is a result of the carbon atom forming four equivalent bonds in three-dimensional space. In this geometry, the fluorine atoms are positioned at the corners of a regular tetrahedron, and the bond angles between them are approximately 109.5 degrees. Because of this symmetrical arrangement, the bond dipoles point outward from the central carbon atom and are evenly spaced.
The vector nature of dipole moments means that their directions and magnitudes determine the overall molecular polarity. In CF₄, the dipole vectors of the C–F bonds are equal in strength but point in directions that are symmetrically opposite. This causes the dipole moments to cancel each other out, much like pulling equally in four different directions on a central point results in no movement.
As a result of this perfect symmetry and cancellation of dipole moments, CF₄ does not have a net dipole moment and is therefore classified as a nonpolar molecule, even though the individual bonds within it are polar. This principle of symmetry overriding bond polarity is common in molecules with highly symmetrical geometries.
