Structural characterization of bulk ZnWO4 prepared by solid state method

Uniform crystals of ZnWO4 have been synthesised from the equimolar mixtures of ZnO and WO3 by conventional solid state method. For the first time the sample has been characterised detailedly to confirm the formation of pure single phase of perovskite ZnWO4. The formation of ZnWO4 has been confirmed by sintering the mixtures of ZnO and WO3 at two different temperatures one at 900 degrees C and other at 1000 degrees C. It is observed that the sample sintered at 1000 degrees C for 24 h shows complete formation of the single phase of ZnWO4. The crystallinity and the phase formation has been confirmed by X-ray diffraction technique. X-ray photoelectron spectroscopy measurements have been carried out for the bulk ZnWO4 sintered at 1000 degrees C for 24 h, showing 16% of Zn, 16% of W and 68% of O indicating stoichiometric ZnWO4. Surface morphology studies by scanning electron microscopy showed uniform crystals of ZnWO4. The purity of the compound has also been checked in depth by Energy Dispersive X-ray method indicating the absence of foreign ions apart from that, the ratio of Zn : W has been calculated and found to be 1 : 1 confirming the stoichiometric ZnWO4 inside the crystals. (C) 2000 Kluwer Academic Publishers.