XAFS study of kesterite, kuramite and stannite type alloys

The multinary solid solution series of the chalcogenides kesterite–stannite and kuramite–stannite are studied by X–ray absorption fine structure spectroscopy. The oxidation state of iron is estimated from the near edge (XANES) spectra. For the kesterite–stannite series the Fe2+ state is found throughout the whole composition range. For the kuramite–stannite series the average oxidation state of Fe changes continuously from trivalent for kuramite to divalent for stannite. The EXAFS results indicate for all iron containing samples substitutional iron tetrahedrally coordinated by 4 sulphur atoms.