Question

why SF6 have zero dipole moment while SF4 have not zero dipole moment ? explain

Answer 1

SF6 has more partial positive and partial negative charge

Answer 2

Answer:

SF6 forms an octahedral structure(as shown in fig.2 ), has symmetrical shapes, individual dipoles get cancelled, therefore, net dipole is zero.

The unsymmetrical 'see-saw' structure of SF4 leads to an overall dipole, as shown. SiF4 is tetrahedral so that the individual dipoles on the Si-F bonds cancel and the molecule has no dipole moment.

Explanation:

The distance between the centers of positive and negative charges and product of the negative or positive charge are the two factors that make up the dipole moment. The more electronegative atom in the compound is where the dipole moment is pointed.  The opposite direction of the dipole moment in the molecule cancels each other.

In case of SF4 (as shown in figure 1)

In comparison to the Sulphur atom, fluorine is more electronegative. As a result, the dipole moment will point at the fluorine atom. The lone pair is not cancelled out because the consequent dipole moments of the other fluorine atom cancel the dipole moment of one fluorine atom. Hence it has a non zero dipole moment.

Zero dipole moment- A dipole moment of zero indicates that there is no partial charge on either end of a covalent bond. Bonds that exhibit this feature are known as polar covalent bonds.

SF6 forms an octahedral structure(as shown in fig.2 ), has symmetrical shapes, individual dipoles get cancelled, therefore, net dipole is zero.

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