Local structure relaxation in nanosized tungstates

• MeWO4 (Me=Co, Ni, Cu, Zn) were prepared by co-precipitation method.
• Local structure of MeWO4 was studied by Raman and x-ray absorption spectroscopies.
• The atomic structure of nanocrystalline MeWO4 is strongly relaxed.
• Distortion of metal–oxygen octahedra is caused by the electron–lattice coupling.

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.