5.1 Stracture of benzene p.154 The Kekule proposal Benzene's unusual structure All its c-c bonds are the same length: 139 pm between single(154 pm) and double (134 pm) bonds Electron density in all six C-C bonds is identical Structure is planar, hexagonal CC- C bond angles 120° Each C is sp and has a p orbital perpendicular to the plane of the six-membered ring 1.5 bonds on average H C H emhm9o%sC幽Benzene’s Unusual Structure: • All its C-C bonds are the same length: 139 pm — between single (154 pm) and double (134 pm) bonds • Electron density in all six C-C bonds is identical • Structure is planar, hexagonal • C–C–C bond angles 120° • Each C is sp2 and has a p orbital perpendicular to the plane of the six-membered ring 5.1 Stracture of Benzene: The Kekule Proposal p.154