Pure and Applied Chemistry

Abstract: Solubility equilibria between solid salts, salt hydrates, and water play an important role in fundamental and applied branches of chemistry. The continuous interest in this field has been reflected by the 15^th International Symposium on Solubility Phenomena as well as by the ongoing IUPAC-NIST Solubility Data Series (SDS), which by now comprises close to 100 volumes. Three typical examples concerning solubility phenomena of ionic solids in aqueous solutions are discussed: (1) sparingly soluble, simple molybdates; (2) sparingly soluble ionic solids with basic anions; and (3) hydrolysis of inert hexa-aqua-M(III) ions, where M is Ir, Rh, or Cr. In the first two cases, essential experimental details are discussed, an outline of thermodynamic analyses is given, and theoretical aspects are emphasized. In the third case, an educational suggestion is made.