A spectrophotometric investigation of the aquomanganese(III) ion in perchlorate media

Abstract

The observed spectrum of the aquomanganese(III) ion in perchlorate media has been analysed into the spectra of the hexa-aquo-ion and the hydroxo-penta-aquo-ion. Both have maxima at 21,000 and ca. 45,000 cm.^–1. The former is identified with a d–d transition involving Jahn–Teller distortion from O_h symmetry, and the latter with a partial ligand → metal electron transfer. The equilibrium between the two species of manganese(III) is examined quantitatively, and values for the heat and entropy of hydrolysis are calculated. These are compared with values for other ions in the first transition series.