Nx-ray studies of crystalline peptides, linus pauling and robert corey found that the c—n bond in the peptide link is intermediate in length (1.32 å) between a typical c—n single bond (1.49 å) and a c=n double bond (1.27 å). they also found that the peptide bond is planar (all four atoms attached to the c—n group are located in the same plane) and that the two α-carbon atoms attached to the c—n are always trans to each other (on opposite sides of the peptide bond). (a) what does the length of the c—n bond in the peptide linkage indicate about its strength and its bond order (i. e., whether it is single, double, or triple)? (b) what do the observations of pauling and corey tell us about the ease of rotation about the c—n peptide bond?