Figure 4.

Newman projection-like depiction of two dihedrals sharing three atoms, using the methylamine to methane transformation as an example (see Figure 3 for the atom labeling). Atoms/bonds in the foreground are drawn in red and atoms/bonds in the background in blue. The methyl carbon C is hidden behind the red circle for H. The two dihedrals φ_{DH4–H–C–H1} and φ_{DH4–H–C–H3} under consideration are indicated in purple and blue, respectively. The difference θ_H1–C–H3^′ between the two dihedrals is colored in green; this is also the angle between the projection of the bonds H₁–C and H₃–C into the plane perpendicular on the bond H–C.