Lanthanide tetrad effects : Extension of Jorgensen's theory and its new developments

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As a case study of thermodynamic data for aqueous Ln(III)-chelate complex formations, those data for Ln(III)-DTPA and Ln-EDTA complex formations have been examined in view of the Jorgensen-Kawabe(JK) equation for the lanthanide tetrad effect. Ln-chelate formations represent such reactions that ligands of H-2O of aqua Ln(III) ions are replaced by(DTPA+H-2O) or(EDTA+H-2O), where. H and. S show similar tetrad effects, but the tetrad effects are cancelled almost totally in. G through. G=. H-T. S. Previous studies overlooked this mechanism, and led to misunderstanding.As an experimental study, REE(Ln+Y) partition coefficients for the pair of BaSO4/aqueous solution have been determined in the temperature range of 10~ 200. C. The tetrad effects of△H and△S for REE partitioning reaction have been shown. Using the Gibbs-Helmholtz equation and JK equation, the tetrad effects have been analyzed.REE abundance patterns of rare-earth minerals(kimuraite and lanthanite) normalized by chondrite, indicate the tetrad effects. We confirmed that the tetrad effects can be well reproduced by JK equation. This is the first demonstration in REE geochemistry that REE compositions of REE minerals can be fitted to the simple theoretical equation.In order help graduate students and young researchers understand the theoretical base of Jorgensen-Kawabe equation, the three textbooks on Statistical Mechanics, Physics on Electricity and Magnetism, Quantum Mechanics have been prepared and registered them in Repository of NU Library for their open uses. Jorgensen-Kawabe equation itself and the results of the present study are discussed and cited in another textbook"REE Chemistry and Geochemistry", which is now in preparation.