Two alternative Lewis structures are proposed for the chlorite ion, ClO₂⁻
CHEMISTRY · Single correct · AP · Chemistry · Compound Structure and Properties · Compound Structure and Properties
Problem
Two alternative Lewis structures are proposed for the chlorite ion, ClO₂⁻.
• Structure X: Cl is single-bonded to both O atoms; each O bears a formal charge of –1, and Cl bears a formal charge of +1.
• Structure Y: Cl is double-bonded to one O and single-bonded to the other; only the singly bonded O bears a formal charge of –1, and Cl has a formal charge of 0.
Which of the following best justifies why Structure Y is the preferred representation?
(a) Structure Y obeys the octet rule for chlorine, whereas Structure X requires an expanded valence shell for chlorine.
(b) Structure Y reduces the magnitude of the positive formal charge on chlorine from +1 to 0, decreasing the overall energy of the ion.
(c) Structure Y places the negative formal charge on an oxygen atom, the most electronegative atom in the ion.
(d) Structure Y predicts identical Cl–O bond lengths, which is consistent with experimental observations for ClO₂⁻.