Microwave-assisted synthesis and characterization of SrMoO₄ and SrWO₄ nanocrystals

SrMoO₄ and SrWO₄ nanocrystals have been synthesized using Sr(NO₃)₂ and Na₂MeO₄ (Me = Mo and W) in ethylene glycol by a microwave irradiation method at 50% of 180 W for 20 min. The product phases were detected using X-ray and selected area electron diffractions. They show the body-centered primitive tetragonal structure with the lattice parameters of a = b = 5.4007 Å and c = 12.0330 Å for SrMoO₄, and a = b = 5.4274 Å and c = 11.9241 Å for SrWO₄. X-ray diffraction patterns of the products, obtained by simulation using CaRIne version 3.1 program, are in accordance with those of the corresponding experiment and International Centre for Diffraction Data. A transmission electron microscope revealed the presence of nanocrystals composing the products, with their sizes in the ranges of 14–40 and 14–38 nm for SrMoO₄ and SrWO₄, respectively. Six different vibrations of ν ₁(A _g), ν ₃(B _g), ν ₃(E _g), ν ₄(B _g), ν ₂(A _g), and ν _f.r.(A _g) were detected using a Raman spectrometer, and the ν ₃(F ₂) antisymmetric stretching and ν ₄(F ₂) bending modes of [MeO₄]²⁻ tetrahedrons using a Fourier transform infrared spectrometer. Photoluminescence emissions of SrMoO₄ and SrWO₄, caused by the ¹ T ₂ → ¹ A ₁ transition of electrons, were detected at 410 and 418 nm, respectively.