Kinetic investigation of the lanthanide(III)-nitrate complexation reaction

Abstract

Using ultrasonic relaxation technique the kinetics of lanthanide nitrate complexation were investigated in the presence of excess nitrate ion for Nd(III), Gd(III), Dy(III) and Er(III). The absorption spectra could most simply be interpreted in terms of a double relaxation. At 25°C the complexation rate constants, k₃₄, were 1.8 × 10⁸ s^–1 for Nd(III) and 0.6 × 10⁸ s^–1 for Er(III). These rate constants were compared with those from earlier lanthanide complexation studies to interpret the overall complexation mechanism. Rate constants could not be obtained for the Dy and Gd systems.