14.3.1 Describe the delocalization of pi electrons and explain how this can account for the structures of some species
- sometimes pi bonds can involve more than 2 atoms (more than 2 electrons)
- result is delocalized pi bond, where the electrons are mobile and shared by a # of atoms
- eg. benzene has delocalized pi bonds
- the carbon forms sigma bonds with other carbons in the ring (sp2 hybridization)
- one p orbital per carbon is not hybridized --> these all interact to form delocalized pi bond
- pi bond is like a ring above and below the carbon ring
- resulting bonds all equal length, mid-way between 2 resonance structures
- why double bonds can't rotate: the location above and below the plane means it would need to be broken and re-formed