Two nonequivalent Lewis structures can be drawn for COCl
CHEMISTRY · Single correct · A Level · Chemistry · Bonding · Bonding
Problem
Two nonequivalent Lewis structures can be drawn for COCl2.
Structure I: carbon is double-bonded to oxygen and single-bonded to each chlorine atom; every atom has an octet and all formal charges are zero.
Structure II: carbon is single-bonded to oxygen (which carries three lone pairs) and single-bonded to each chlorine atom; carbon has a +1 formal charge and oxygen has a –1 formal charge.
Which statement about these two structures is most accurate?
(a) Structure II is more plausible because it places the negative charge on the more electronegative oxygen atom.
(b) Both structures contribute equally to the resonance hybrid because the overall formal charge of each is zero.
(c) Structure I is more plausible because it minimizes formal charges while satisfying the octet rule for every atom.
(d) Structure I is less plausible because double-bonding oxygen gives oxygen a +1 formal charge, making Structure II preferred.