Beryllium(II) hydrolysis in 3.0 mol dm-3 perchlorate

The complex-formation equilibria in the system Be11-H2O have been studied at 25 0C by means of e.m.f. methods, using a coulometric titration technique, in 3.0 mol dm-3 (Na)ClO4 solutions. The ranges of total beryllium(II) concentration and acidity were 80 > = B >= 1 mmol dm-3 and 2 < = - log h < = 6.2 respectively. Previously reported information on beryllium(II) hydrolysis is reviewed and an attempt is made to correlate the data in different ionic media by using the Bronsted-Guggenheim-Scatchard specific ion interaction theory. The values of the equilibrium constants at infinite dilution derived from this approach are log β210 = -3.47 +- 0.05, log β330 = -8.86 +- 0.05, log β560 = -19.5 +- 0.1, and log β680 = -26.3 +- 0.1. Tentative structures for the polynuclear hydroxo complexes are proposed and discussed. The solubility product of α- Be(OH)2(s) has been re-evaluated by using literature data and the hydrolysis constants of this study, at l = 0, log Ksub(so) = -6.87 +- 0.05. (author)