Determining the structure of tetragonal Y2WO6 and the site occupation of Eu3+ dopant

The compound Y2WO6 is prepared by solid state reaction at 750 °C using sodium chloride as mineralizer. Its structure is solved by ab-initio methods from X-ray powder diffraction data. This low temperature phase of yttrium tungstate crystallizes in tetragonal space group P4/nmm (No. 129), Z=2, a=5.2596(2) Å, c=8.4158(4) Å. The tungsten atoms in the structure adopt an unusual [WO6] distorted cubes coordination, connecting [YO6] distorted cubes with oxygen vacancies at the O2 layers while other yttrium ions Y2 form [YO8] cube coordination. Y3+ ions occupy two crystallographic sites of 2c (C4v symmetry) and 2a (D2d symmetry) in the Y2WO6 host lattice. With Eu3+ ions doped, the high resolution emission spectrum of Y2WO6:Eu3+ suggests that Eu3+ partly substituted for Y3+ in these two sites. The result of the Rietveld structure refinement shows that the Eu3+ dopants preferentially enter the 2a site. The uniform cube coordination environment of Eu3+ ions with the identical eight Eu–O bond lengths is proposed to be responsible for the intense excitation of long wavelength ultraviolet at 466–535 nm.

The excitation and emission spectra of Y2WO6:Eu3+ indicates the effect of long wavelength-excited property, which is ascribed to the cube coordination environment of Eu3+ ions with the uniform Eu–O bond length.Figure optionsDownload as PowerPoint slideResearch highlights
► Y2WO6 is prepared using sodium chloride as mineralizer.
► The structure of the compound Y2WO6 is solved by ab-initio methods.
► The site occupation of Eu3+ is determined.
► The cube coordination of Eu3+ ions is responsible for the long wavelength excitation.