Local structure relaxation in nanosized tungstates

The atomic structure of nanosized and microcrystalline tungstates MeWO4 (Me=Co, Ni, Cu, Zn), synthesized by co-precipitation technique, has been studied by x-ray absorption spectroscopy at the W L3-edge and Co/Ni/Cu/Zn K-edges, x-ray diffraction, Raman and Fourier transform infrared spectroscopies. The distortion of metal–oxygen octahedra is caused by the electron–lattice coupling and is further enhanced in nanosized tungstates due to formation of the double tungsten–oxygen bonds at the nanoparticle surface.