Ligand Exchange and Nature of Luminescence Centers in the Crystals of Uranyl Nitrates and Perchlorates.

We obtained complexes of uranyl nitrates and uranyl perchlorates with neutral ligands in crystalline and amorphous states and also with variable composition (as regards both water and the quantity of acid ligands entering into the first coordination sphere of UO₂ ²⁺). We studied their luminescence spectra at T = 77 K. Correlation between the frequencies of electronic and vibronic transitions and the donor numbers of neutral ligands has been established. The possible ways of replacing neutral ligands in the first coordination sphere of UO₂ ²⁺ have been analyzed as well as the composition and structure of the complex systems formed in this case. [ABSTRACT FROM AUTHOR]