Pattern formation in a class of homogeneous photochemical reactions

Based on earlier observations of Avnir et al. [D. Avnir, M.L. Kagan, W. Ross, Chem. Phys. Lett. 135 (1987) 177; D. Avnir, M.L. Kagan, Chaos 5 (1995) 589] we investigated the kinetics of the spatial structures of the precipitate, Turnbull-blue, formed in aqueous mixtures of potassium ferrioxalate plus potassium ferricyanide under continuous laser illumination. Similar structures were observed when ferricyanide was replaced by some other Fe2+ ions reagent. Spatio-temporal and thermochemical analyses led us to the conclusion that the formation of the dissipative structures is due to convection which, in turn, is greatly affected by the heat of reaction.