ABSTRACT
Originally, chemical oscillations were imagined as a sort of perpetual motion machines in a beaker. Therefore, they were simply ignored. However, this belief has been shattered by the discovery of several oscillatory reactions in the last one hundred years, or so. The essential requirement for any chemical system to originate phenomena of temporal self-organization is to be far-from-equilibrium. Moreover, it is necessary the interplay of processes of positive and negative feedbacks in the presence of a time delay between them. Alternatively, an adequately delayed negative feedback process in a reaction network can give rise to oscillations. Chemical oscillations rely on rather complicated mechanisms because they usually involve many species and many steps. However, all the homogeneous isothermal reactions can be sorted into five main families of “primary oscillators.” Such classification is based on a minimal set of reactions essential to observe oscillations. The study of the features of the five “primary oscillators” will favor the design of new oscillatory chemical reactions.
