The effect of temperature on the complexation of Cm(III) with nitrate in aqueous solutions

The complexation of curium(III) with nitrate was studied at different temperatures (10-85 degrees C) by luminescence spectroscopy. The stability constants of CmNO(3)(2+) were calculated from the luminescence emission spectra. The specific ion interaction approach (SIT) was used to obtain the stability constants of CmNO(3)(2+) at infinite dilution and variable temperatures. The complexation is weak and little effect of temperature on the complexation was observed over the temperature range 10-85 degrees C. Data on the luminescence lifetime indicate that each nitrate ligand replaces two water molecules from the inner coordination sphere of Cm(3+), forming a bidentate inner-sphere complex with Cm(3+) in aqueous solutions.