Theoretical treatment of the complexation of element 106, Sg, in HF solutions

Abstract

SummaryFully relativistic density-functional calculations of the electronic structures of various oxo-fluoro-complexes were performed for group-6 elements Mo, W, and element 106, Sg. Based on the electronic density distribution data, relative values of the free energy change of complex formation reactions in HF solutions have been defined. On their basis, sequences in the sorption of Mo, W, and Sg by an anion exchange resin (Kdvalues) have been predicted. The results show a complex situation depending on the acid concentration and pH of the solution. The predicted trends are in agreement with the known data for Mo and W. The following sequence in the sorption of Mo, W, and Sg by an anion exchange resin from 5×10-3HF/0.1 M HNO3solutions is predicted: Mo>Sg>W. A very good separation of Sg from Mo and W is expected at concentrated HF solutions, where MOF5-is formed. The sequence of the sorption in this case should be Sg ≫W > Mo.