ABSTRACT
The reaction of carbonate ion dissociation in molten CsI and NaI was studied in the temperature range from the melting point to 800 (CsI) and 830 degrees C (NaI) by a potentiometric method with the use of a membrane oxygen electrode as an indicator one. The dissociation constant of CO(3)(2-) in the molten iodides was found to increase with the temperature. pK values for CsI are 4.47 (650 degrees C), 4.23 (700 degrees C), 3.89 (750 degrees C), 3.44 (800 degrees C); those for NaI are 4.68 (700 degrees C), 4.39 (750 degrees C), 4.17 (800 degrees C), 3.92 (830 degrees C). The plots of pK vs reverse temperature are linear. Carbonate stability in molten CsI is lower than that in the NaI due to lower stability of Cs(2)CO(3) compared with Na(2)CO(3).