Structural change of aqueous lanthanum chloride solution by hydrolysis

摘要

The structural variation of lanthanum chloride solution in hydrolysis was investigated by X-ray radial distribution function. The radial distribution functions for five solutions (C 3.7M, 3.0M, 2.0M, 1.0M, 0.5M) showed a peak at Ca. 2.7A and a shoulder at ca. 3.2A. The former was assigned to La~(3+)-H_2O and H_2O-H_2O correlation. The latter was assigned to H_2O-H_2O interaction around La~(3+) and Cl-H_2O interaction. In the diffraction patterns, a peak was observed at 6 approx 10A, which shows the evidence or high-order structure among La~(3+) ions. The variations of the adiabatic compressibility and the other physicochemical properties with the composition and reaction time of the hydrolysis showed the evidence of the hydroxo complex.