The hydrolysis of the cerium(III) ion, Ce3+, in aqueous perchlorate solutions at 500C

The hydrolysis equilibria of the Ce3+ ion have been studied at 500C by measuring, with a glass electrode, the hydrogen ion concentration of Ce(ClO4)3 solutions. The Ce(III) concentration ranged from 0.1 to 1 m, while the ClO-4 level was kept constant at 3 m by adding LiClO4. Solutions containing hydrolysed species, in which at the most 0.4% of the Ce3+ can be transformed into reaction products without the formation of a precipitate, were prepared by constant-current coulometry. The potentiometric data have been explained in terms of Ce(OH)2+, Ce2(OH)5+ and Ce3(OH)4+5 complexes. Their formation constants in the inert 3 m LiClO4 medium are reported. (author)