Hydroxide complexes of cerium(III).

From the experimentally determined borderline of precipitation in the pM'-pH diagram the stability constants of the mononuclear and polynuclear species of cerium hydroxide have been determined graphically. The stability constants found are log*beta(1) = -8.1, log*beta(2) = -16.3, log*beta(3) = -26.0, log*beta(5,3) = -32.8 and log*K(s0) = 20.1. These values refer to freshly prepared precipitates, at room temperature and an ionic strength of 1, and are precise to about 0.2 log units.