Stoichiometry of precipitation under conditions of double diffusion

Abstract

The mechanism of natural precipitation processes has been studied using as a model system the one-dimensional double diffusion of the precipitating components in a gel. It was found, theoretically and experimentally, that precipitation under conditions of double diffusion occurs when the equivalent concentrations of both precipitating components are equal to a “critical” concentration. Under the experimental conditions used here the conventional solubility law does not apply. A general relation is deduced which enables the estimation of the relative error in the determination of the critical concentration for precipitation. Theoretical treatments of other authors are discussed.