Résumé
The geochemical behavior of Sb under reducing conditions is closely linked to the formation of digenetic iron sulfides. Since very few data is currently available on Sb speciation in such minerals, including pyrite (FeS2) ubiquitously found in surface environments, we aim at obtaining molecular scale information by performing XANES/EXAFS measurements at the Sb K-edge (30,491 eV) on synthetic FeS and FeS2 samples representative of continental sedimentary surface environments. Redox and structural information gained from XAS spectroscopy will be used together with Sb concentrations in solutions (ICP-MS), and with XRD measurement. such information is crucial to uncover the steps of Sb biogeochemical cycle in reducing surface environments and to propose conceptual models for Sb speciation in soil and sedimentary reservoirs.