Mixed complexes of alkaline earth uranyl carbonates: A laser-induced time-resolved fluorescence spectroscopic study

The interaction of the alkaline earth ions Mg2+, Sr2+ and Ba2+ with the uranyl tricarbonato complex has been studied by time-resolved laser-induced fluorescence spectroscopy. In contrast to the non-luminescent uranyl tricarbonato complex at ambient temperature the formed products show luminescence properties. These have been used to determine the stoichiometry and complex stabilities of the formed compounds. As the alkaline earth elements are located in an outer shell of the complex the influence of the type of the alkaline earth element on the stability constant is not very drastic.The stability constants range from log β1 1 3°=26.07±0.13log β1 1 3°=26.07±0.13 to log β1 1 3°=26.93±0.25log β1 1 3°=26.93±0.25 for the first reaction step and from log β2 1 3°=29.73±0.47log β2 1 3°=29.73±0.47 to log β2 1 3°=30.79±0.29log β2 1 3°=30.79±0.29 for the overall complex formation with two alkaline earth ions.