SOME MEASUREMENTS ON THE IRON (111)–THIOCYANATE SYSTEM IN AQUEOUS SOLUTION

Abstract

A spectrophotometric study of the ferric thiocyanate system is reported. The temperature and ionic strength of the solutions were carefully controlled, and suitable precautions were taken against fading. From the data, values of the equilibrium constant for the formation of FeSCN++ from simple ions, and of the extinction coefficients of FeSCN++ were obtained for different temperatures and ionic strengths, with results that differed somewhat from earlier values. The effect of varying acidity was also investigated. From more concentrated solutions, values for the equilibrium constants for the formation of Fe(SCN)2+ and Fe(SCN)3 were obtained; it was not necessary to postulate higher complexes.