HAVREZ,PAUL AND HIS BENZENE FORMULA

The belgian chemist Paul Havrez (1838-1875) proposed two highly symmet rical, space-filling models for the benzene molecule, only a few month s after Kekule's seminal proposal of a cyclic benzene structure. One o f these models is characterized by the revolutionary assumption of equ al 3/2 bonds between all neighbouring carbon atoms, in sharp contrast to Kekule's formula with alternating double and single bonds. With con siderable hind sight, Havrez's model could be considered as a forerunn er of the benzene structure with delocalized pi bonds.