Formation of Liesegang patterns

It has been recently shown that precipitation bands characteristic of Liesegang patterns emerge from spinodal decomposition of reaction products in the wake of moving reaction fronts. This mechanism explains the geometric sequence of band positions xn Q(1+p)n and, furthermore, it yields a spacing coefficient p that is in agreement with the experimentally observed Matalon–Packter law. Here I examine the assumptions underlying this theory and discuss the choice of input parameters that leads to experimentally observable patterns. I also show that the so-called width law relating the position and the width of the bands wn xn follows naturally from this theory.