Chapter 1, Problem 70DSP

Amide Lewis Structural Formulas

Lewis formulas are the major means by which structural information is communicated in organic chemistry. These structural formulas show the atoms, bonds, location of unshared pairs, and formal charges.

Two or more Lewis formulas, differing only in the placement of electrons, can often be written for a single compound. In such cases the separate structures represented by the Lewis formulas are said to be in resonance, and the true electron distribution is a hybrid of the electron distributions of the contributing structures.

The amide function is an important structural unit in peptides and proteins. Formamide, represented by the Lewis structure shown, is the simplest amide. It is a planar molecule with a dipole moment of $3.7$

D. Lewis structures I–IV represent species that bear some relationship to the Lewis structure for formamide.

Which Lewis formula is both planar according to VSEPR

and a resonance contributor of formamide?

I

II

III

IV