Which of the following ions possess a dipole moment?

Question

(a) ClF2+
has a dipole moment
has no dipole moment
cannot be determined
(b) ClF2−
has a dipole moment
has no dipole moment
cannot be determined
(c) IF4+
has a dipole moment
has no dipole moment
cannot be determined
(d) IF4−
has a dipole moment
has no dipole moment
cannot be determined

Can someone explain how to know what has a dipole moment after drawing the structure? I understand that the more electronegative the atom is where the dipole points to but what effect does the ionic compound charges have on whether it has a dipole moment? Thanks

Answer 1

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The charge of the ionic compound does not affect whether it has a dipole moment. The dipole moment is determined by the difference in electronegativity between the atoms in the compound. If the difference in electronegativity is greater than 0.4, then the compound will have a dipole moment. For example, in ClF2+, the difference in electronegativity between chlorine and fluorine is greater than 0.4, so it has a dipole moment. On the other hand, in IF4+, the difference in electronegativity between iodine and fluorine is less than 0.4, so it does not have a dipole moment.