A Spectrophotometric Study on Uranyl Nitrate Complexation to 150°C

摘要

The formation constant of the mononitratouranyl complex was studied spec-trophotometrically at temperatures of 25, 40, 55, 70, 100 and 150°C (298, 313,328, 343, 373 and 423 K). The uranyl ion concentration was fixed at approximately 0.008 mol centre dot kg~(-1) and the ligand concentration was varied from 0.05 to 3.14 mol centre dot kg~(-1). The uranyl nitrate complex, UO2NO_3~+, is weak at 298 K but its equilibrium constant (at zero ionic strength) increases with temperature from log_(10) beta_1 = -0.19 ± 0.02 (298 K) to 0.78 ± 0.04 (423 K).