Structure of Fe/Co/Ni hexacyanoferrate as probed by multiple edge X-ray absorption spectroscopy.

The structural parameters in selected cobalt and mixed cobalt/nickel hexacyanoferrates have been determined by X-ray absorption spectroscopy. The presence of two or three metals in the sample requires the use of a highly efficient multiple edge analysis. The typical structure of mixed hexacyanoferrates coupled with a suitable data analysis program, GNXAS, allow us to determine structural parameters considering a very high number of experimental points. The first data analysis of three contiguous edges (Fe, Co, and Ni K-edges), the structural parameters of which are entirely correlated, is presented. The advantages and limitations of the multiple edge approach are underlined and placed in the context of the previous studies. The CN bond length has been determined with a statistical error of few thousandths of an angstrom.