X-RAY PHOTOELECTRON SPECTROSCOPIC STUDIES OF THE CHARGED STATE OF 3<i>d</i> METAL IONS IN CuCr<sub>1-<i>x</i></sub>V<sub><i>x</i></sub>S<sub>2</sub> (<i>x</i> = 0-0.4)
The charged state of the 3<i>d</i> metal ions in layered cation-substituted disulfides CuCr<sub>1-<i>x</i></sub>V<sub><i>x</i></sub>S<sub>2</sub> was studied by X-ray photoelectron spectroscopy. An analysis of the energy positions and structure of the Cu2<i>p</i><sub>3/2</sub> and Cr2<i>p</i><sub>3/2</sub> X-ray photoelectron lines showed that the corresponding polycrystalline samples of CuCr<sub>1-<i>x</i></sub>V<sub><i>x</i></sub>S<sub>2</sub> contained mixed-valence chromium and copper ions. It was shown that the charged states of chromium and copper ions depended on the concentration of vanadium cations (<i>x</i>). The presence of mixed-valence Cu<sup>1+</sup> and Cu<sup>2+</sup> ions in CuCr<sub>1-<i>x</i></sub>V<sub><i>x</i></sub>S<sub>2</sub> may be correlated with the crystal structure of the corresponding layered disulfides.