Theoretical models of the Liesegang phenomena are studied and simple e
xpressions for the spacing coefficients characterizing the patterns ar
e derived. The emphasis is on displaying the explicit dependences on t
he concentrations of the inner and the outer electrolytes. Competing t
heories (ion-product supersaturation, nucleation and droplet growth, i
nduced sol-coagulation) are treated with the aim of finding the distin
guishing features of the theories. The predictions are compared with e
xperiments and the results suggest that the induced sol-coagulation th
eory is the best candidate for describing the experimental observation
s embodied in the Matalon-Packter law. (C) 1998 American Institute of
Physics, [S0021-9606(98)50145-6].