Nanocrystalline ZnWO4 powders were successfully synthesized from a water-based citric acid complex precursor using microwave irradiation. The polymeric precursors were heat treated at temperatures from 300 to 600 oC for 3 h. Crystallization of the ZnWO4 was detected at 400 oC and entirely completed at a temperature of 600 oC. The powders at 400 and 500 oC showed primarily a co-mixed morphology with spherical and silkworm-like forms. The powders at 500 oC had a relatively more homogeneous morphology, while the powders at 600 oC showed a relatively exaggerated growth a including rectangular form. The average crystalline sizes were 18~25 nm, showing an ordinary tendency to increase with temperature from 400 to 600 oC.

Keywords: Microwave-assisted synthesis, nanocrystalline powders, ZnWO4, water-based citric acid complex precursor