Spectrophotometric and calorimetric study of the gallium(III) monothiocyanate complex in dimethyl sulphoxide solutions

The stability constant of gallium(III) monothiocyanate in DMSO at 25 °C has been determined spectrophotometrically using equimolar mixtures of gallium(III) and iron(III) perchlorates as constant-ionic-strength media. Formation of the complex has been studied calorimetrically. The derived thermodynamic parameters are: ΔG°=–20.0 ± 0.7 kJ mol–1, ΔH°= 11.1 ± 0.2 kJ mol–1 and ΔS°= 104 ± 3 J K–1 mol–1.