Structural analysis and optical properties of the Bi_2−xY_xWO₆ system

Abstract

The structural and optical properties of the Bi2–xYxWO6, system are reported.

Synthesis and Characterization of Yellow Pigments of Bi1.7RE0.3W0.7Mo0.3O6 (RE = Y, Yb, Gd, Lu) with High NIR Reflectance

“…When the RE/Mo are doped in Bi 2 WO 6 according to the formula Bi 1.7 RE 0.3 W 0.7 Mo 0.3 O 6 , the orthorhombic phase transforms. All of the doped samples show a pure and monoclinic phase with a space group of A 2/ m , which is similar to previous reports. ,, The diffraction peaks of Bi 1.7 RE 0.3 W 0.7 Mo 0.3 O 6 are similar to BiNdWO 6 (JCPDS Card No. 34-0057).…”

Impact of Average, Local, and Electronic Structure on Visible Light Photocatalysis in Novel BiREWO6 (RE = Eu and Tb) Nanomaterials

“…Further, based on difference Fourier maps, they have introduced positional disorder for the tungsten as well as some of the oxygen atoms resulting in a twofold rotational disorder in the WO 6 octahedron around the a-axis to improve the Rietveld refinement. Pasternak et al 30 used the ordered model for the Rietveld refinement of Bi 2−x Y x WO 6 monoclinic phase nanoparticles. Therefore, to verify which model would be suitable for our nanomaterials, we have carried out refinement with both HT-Bi 2 WO 6 (ordered) and BiNdWO 6 (disordered) models on the neutron and synchrotron data.…”

“…Hence, in this study, we employ GGA + U (where U is the intraorbital electron repulsion parameter) calculations to explicitly account for the electron−electron repulsions. 30 The unit cell parameters were constrained to those obtained from the X-ray diffraction (XRD) experiments in this study, and the ions were allowed to relax until the Hellman−Feynman forces were less than 0.01 eV/A on each atom.…”

“…Because of the strong electron correlations present in the system by virtue of higher transition metal and RE ions, both the local density approximation (LDA) and the GGA predict a metallic ground state for the RE-substituted systems. Hence, in this study, we employ GGA + U (where U is the intraorbital electron repulsion parameter) calculations to explicitly account for the electron–electron repulsions . The unit cell parameters were constrained to those obtained from the X-ray diffraction (XRD) experiments in this study, and the ions were allowed to relax until the Hellman–Feynman forces were less than 0.01 eV/A on each atom.…”

“…29 This positional disorder of the tungsten and three of the oxygen atoms were considered in the Rietveld refinement of this material. Pasternak et al 30 carried the Rietveld refinement on the laboratory X-ray data of Bi 2−x Y x WO 6 monoclinic phases obtained by a sol−gel method using both ordered (HT-Bi 2 WO 6 ) and disordered (BiNdWO 6 ) models which yields a similar fit. However, to the best of our knowledge,there is no report on the detailed crystal structure and band structure of BiREWO 6 nanomaterials.…”