Some important aspects of the chemistry of iso- and heteropolyanions
stoicheiometric compositions is indicated. Figure 2 shows their correlation with the very distinct equivalent points of the potentiometric titration curve1• In this example, the degree of condensation increases with x, the final member of the series being the insoluble acid; a great many systems behave similarly, but for some others, particularly when the acid is weak and soluble, the proportion of condensed ions goes through a maximum. Such is the case