XPS AND XANES STUDY OF LAYERED MINERAL VALLERIITE
Yu.L. Mikhlin1, A.S. Romanchenko1, E.V. Tomashevich1, M.N. Volochaev2, Yu.V. Laptev3
1Institute of Chemistry and Chemical Technology, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia
2Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia
3Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: валлериит, рентгеновская фотоэлектронная спектроскопия высоких энергий, TEY XANES, valleriite, high energy X-ray photoelectron spectroscopy
Abstract
Mineral valleriite of the Talnakh deposit, which consists of alternating copper-iron sulfide layers and brucite-like layers of magnesium-aluminium hydroxide is studied for the first time by XPS at photon excitation energies ranging from 1.253 keV to 6 keV and CuL FeL, SL, AlL, MgK, and OK edge TEY XANES using synchrotron radiation. The comparison of the XPS and XANES spectra of valleriite and chalcopyrite, in particular, demonstrates that in the sulfide layers of valleriite, Cu+ and Fe3+ are in a tetrahedral coordination, however, a local positive charge on both cations is slightly lower than that in chalcopyrite, apparently, due to a structure disorder. The concentration of oxygen-bound iron decreases with an increase in the depth of the analyzed layer even after ion etching; probably, Fe does not enter into the brucite-like layer, but mainly forms its own surface structures.
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