ИСТИНА

We use X-ray absorption spectroscopy of synthetic crystals to investigate the substitution mechanisms in sphalerite containing In together with the group 11 metals. All the admixtures (Ag, Cu, In) are homogeneously distributed within the sphalerite matrix. In all studied samples In3+ replaces Zn in the structure of sphalerite. The In-ligand distance increases by 0.17 Å and 0.1 Å for the 1st and 2nd coordination shells, respectively, in comparison with pure sphalerite. The InS distance in the 3rd coordination shell is close to the one of pure sphalerite. Our data suggest that both Ag and Cu in the presence of In exist in the solid solution state, where the metals are tetrahedrally coordinated with S atoms. Results of the present study demonstrate that in sphalerite, containing the group 11 metals (Cu, Ag, Au) together with In, an isomorphous substitution mechanism by the charge compensation scheme 2Zn2+↔Me++Me3+ is implemented.