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The discovery of this chemical reaction is credited to Boris Belousov. He noted, some time in the 1950s that in a mix of potassium bromate, cerium(IV) sulfate, malonic acid, and citric acid in dilute sulphuric acid, the ratio of concentration of the cerium(IV) and cerium(III) ions oscillated, causing the colour of the solution to oscillate between a yellow solution and a colorless solution. This is due to the cerium(IV) ions being reduced by malonic acid to cerium(III) ions, which are then oxidized back to cerium(IV) ions by bromate(V) ions. Belousov made two attempts to publish his finding, but was rejected on the grounds that he could not explain his results to the satisfaction of the editors of the journals to which he submitted his results.Soviet biochemist Simon El'evich Shnoll encouraged Belousov to continue his efforts to publish his results. His work was finally published in a less respectable, nonreviewed journal. After Belousov's publication, Schnoll gave the project in 1961 to a graduate student, Anatol Zhabotinsky, who investigated the reaction sequence in detail;however, the results of these men's work were still not widely disseminated, and were not known in the West until a conference in Prague in 1968. A number of BZ cocktails are available in the chemical literature and on the web. Ferroin, a complex of phenanthroline and iron, is a common indicator (used in the youtube video clip below). These reactions, if carried out in petri dishes, result in the formation first of colored spots. These spots grow into a series of expanding concentric rings or perhaps expanding spirals similar to the patterns generated by a cyclic cellular automaton. The colors disappear if the dishes are shaken, and then reappear. The waves continue until the reagents are consumed. The reaction can also be performed in a beaker using a magnetic stirrer. The Belousov-Zhabotinsky reaction is a complex mixture of chemicals in which repeating patterns of oxidation propagate regularly.

Press the play button below to see the youtube video clip.
A Belousov–Zhabotinsky reaction, or BZ reaction, is one of a class of reactions that serve as a classical example of non-equilibrium thermodynamics, resulting in the establishment of a nonlinear chemical oscillator. The only common element in these oscillating systems is the inclusion of bromine and an acid. The reactions are theoretically important in that they show that chemical reactions do not have to be dominated by equilibrium thermodynamic behavior. These reactions are far from equilibrium and remain so for a significant length of time and evolve chaotically. In this sense, they provide an interesting chemical model of nonequilibrium biological phenomena, and the mathematical models of the BZ reactions themselves are of theoretical interest and simulations