Theoretical isotope fractionation of cadmium during complexation with organic ligands

Cadmium (Cd) isotopes are an important tool to better understand the inorganic and organic geochemistry of Cd. Organic ligands play a key role control toxicity mobility Cd in living organisms also terrestrial aquatic environments. Therefore, knowledge equilibrium isotope fractionation with is crucial further advance source process tracing field biogeochemistry. In this study, we calculated reduced partition function ratios (103ln?) various complexes by density functional theory. The calculations revealed that 103ln? 114Cd/110Cd for these decreased order Cd(Hcit)(H2cit)? > Cd(cit)(H2O)3? CdH(cit)(H2O)4 CdEDTA Cd(his)2H2O Cd(cit)24? ? Cd(H2O)62+ Cd(H2O)42+ Cd(cys)(H2O)32+ Cd(GS)2(H2O)22? Cd(DMPS)(H2O)2? Cd(DMPS)24? at 0–100 °C. general, heavier preferably bind oxygen nitrogen donor atoms while lighter sulfur ligands. Thus, previously observed immobilization light could be related detoxification processes sulfur. predicted will strengthen as improve understanding cycling systems.