Why is a #"C"="N"# double bond shorter than a #"C"="C"# double bond?

1 Answer
Jun 4, 2015

Nitrogen has a smaller atomic radius from the periodic table trend of increased #Z_(eff)# from left to right, so the internuclear distance in a C=N bond for optimal orbital overlap is closer than for a C=C bond.

The optimal internuclear distance is shown in a potential energy curve similar to this one: