Electronic states and local structures of the photomagnetic Cu-Mo cyanides Cu2Mo(CN)8·8H2O and Cs0.5Cu1.75Mo(CN)8·1.5H2O studied by x-ray absorption fine structure spectroscopy

The electronic states and local structures of photomagnetic CuMo cyanides, Cu2Mo(CN)8·H2O and Cs0.5Cu1.75Mo(CN)8·1.5H2O, have been studied by Cu and Mo K-edge x-ray-absorption fine-structure spectroscopy. A direct evidence for the reduction of divalent Cu to monovalent is detected by Cu K-edge x-ray-absorption near-edge structure. The extended x-ray-absorption fine-structure confirms that the interatomic distances around Cu and Mo in the photoinduced phase are almost identical to those of the initial low-temperature phase. The higher-nearest neighbor coordination numbers, however, are apparently reduced. We have interpreted this as the result of the bending of the Mo-CN bond due to the tetrahedral distortion around the Cu(I) site