Structural Parameters of Ion Coordination in Aqueous Solutions of Cerium Nitrate According to the X-Ray Diffraction Analysis

Based on the experimental data of the X-ray diffraction analysis, radial distribution functions are calculated in a wide concentration range of aqueous cerium nitrate solutions under standard conditions. Different models of the structural organization of systems are elaborated. By the calculation of theoretical functions for each model and their comparison with the experimental ones the optimal variants are revealed. Quantitative characteristics of the structure of the nearest environment of Ce³⁺ and \(\text{NO}^{-}_3\) ions, such as coordination numbers and interparticle distances, are determined along with the types of ionic pairs. The structure of the saturated solution is found to be governed by non-contact ion triples. A decrease in the concentration leads to their transformation into ionic pairs.