Lanthanide phosphate stability constants

There are very few measurements upon which an assessment of lanthanide phosphate stability constants can be based (Byrne and Bingler 1989). The recommended constants... 

While lanthanide phosphate and carbonate stability constants increase substantially between La and Lu, the complexation behavior of lanthanides with sulfate changes very little across the lanthanide series. This difference in complexation constant trends is consistent with inner sphere (COj ) versus outer sphere (SO ) complexation behavior (Byrne and Li 1995). Stability constants for lanthanide sulfate complexes at 25 C and zero ionic strength could be well represented as logso4l8i(M) = 3.60d=0.08. The recommended stability constants (25 C, 0.7 mol kg ionic strength) shown in table 5 are based upon the works of Spedding and Jaffe (1954) and Powell (1974). Following the activity coefficient estimates of Millero and Schreiber (1982) and Cantrell and Byrne (1987a), lanthanide sulfate stability constants, expressed in terms of free-ion concentrations, were calculated as log 504 1 = log SO4/3 - 1.67. 

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