Papers by Keyword: MWO₄

Abstract: MWO4 (M = Ca, Sr, Ba and Pb) was solvothermally prepared using metallic nitrates and sodium tungstate in 25/5 volume ratios of glycerol/water (SGL) and propylene glycol/water (SPG) at 160 oC for 6 h. XRD revealed the presence of MWO4 single phase with tetragonal scheelite structure. The strong W-O stretching band of WO4 tetrahedrons was detected at 705-875 cm-1. The product images show nano-sized particles in basic SGL and SPG solvents and flower-like particles in SPG solvent with pH of 6.7. Central peaks of the luminescent spectra are 445, 446, 443 and 440 nm, respectively.

Abstract: Nano-sized MWO4 and MMoO4 (M = Ca, Ni) powders, which have scheelite and wolframite type structure, were successfully synthesized at low temperatures by a modified citrate complex method assisted by microwave irradiation. The citrate complex precursors were heattreated at temperatures from 300 to 600 °C for 3 h. Crystallization of the MWO4 and MMoO4 precursors was detected at 400 °C and completed at a temperature of 500 °C. Most of the MWO4 and MMoO4 powders heat-treated between 300 and 600 °C showed primarily spherical and homogeneous morphology. The average crystallite sizes of MWO4 (M = Ca, Ni) were between 22 and 39 nm, and those for MMoO4 (M = Ca, Ni) were between 19 and 35 nm respectively, showing an ordinary tendency to grow with temperature.