Thermodynamic Data of Rare Earth Bromates and Chlorates in Aqueous Solutions at 25.0 °C

Abstract

Mean molal activity coefficients, osmotic coefficients, and water activities of the rare earth bromates in aqueous solutions at (25.0 ± 0.1) °C have been determined from dilute to saturated solutions for aqueous lanthanide bromates and chlorates, and conductance data in dilute solutions are also presented. The isopiestic method was employed to obtain the osmotic coefficients, with subsequent computations of the mean molal activity coefficients and water activities. From the conductance data, the rare earth bromate solutions are shown to contain predominantly inner-sphere complexes, and the bromates may exist as the dibromate complexes in dilute solution. The 3β(0)/2 values of Pitzer's equation of rare earth nitrates are comparatively lower than those of the chlorides, perchlorates, and bromides, and the values for the rare earth bromates are even lower. From the thermodynamic data, the trend would indicate that the bromates would have a more attractive interaction than the nitrates. The trend implied that...