ABSTRACT
The view that each different chemical substance may be associated with a fixed molecular structure, and that this structure could be eluci dated by chemical means, was of central importance in the development of modem chemical thinking. Indeed, as Hein [26] has commented, this constract ‘^ a y be the most fruitful conceptual scheme in all of the his tory of science”. The scheme is usually designated nowadays as stmcture
theory, following upon introduction of the term ‘molecular structure’ by Butlerov [39] in 1861. The evolution of the concept, with evaluations of the pioneering contributions of workers such as Butlerov, Couper, Crum Brown, and Keknld, has been discussed by Larder [40] and Rx>cke [41], and in the monographs of Russell [42] and Kuznetsov [43]. Difficulties arising from the chemical analysis of compounds and in the visualizar tion of chemical structures made the germination of structure theory a long and convoluted one. This is evidenced in Figure 7, which presents a pictorial illustration of several of the early attempts to formulate a struc ture for the acetic add molecule. In going from DSbereiner’s strsught chain representation of 1822 through Couper’s complex structure of 1858, only Williamson’s formula succeeded in showing the correct stdchiometry. Conper’s formula comes dosest to depicting the actual structure.
