| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1329081 | Journal of Solid State Chemistry | 2011 | 6 Pages |
Single crystals of new oxyborates, Mg5NbO3(BO3)3 and Mg5TaO3(BO3)3, were prepared at 1370 °C in air using B2O3 as a flux. They were colorless and transparent with block shapes. X-ray diffraction analysis of the single crystals revealed Mg5NbO3(BO3)3 and Mg5TaO3(BO3)3 to be isostructural. The X-ray diffraction reflections were indexed to the orthorhombic Pnma (No. 62) system with a=9.3682(3) Å, b=9.4344(2) Å, c=9.3379(3) Å and Z=4 for Mg5NbO3(BO3)3 and a=9.3702(3) Å, b=9.4415(3) Å, c=9.3301(2) Å and Z=4 for Mg5TaO3(BO3)3. The crystal structures of Mg5NbO3(BO3)3 and Mg5TaO3(BO3)3 are novel warwickite-type superstructures having ordered arrangements of Mg and Nb/Ta atoms. Polycrystals of Mg5NbO3(BO3)3 prepared by solid state reaction at 1200 °C in air showed broad blue-to-green emission with a peak wavelength of 470 nm under 270 nm ultraviolet excitation at room temperature.
Graphical abstractSingle crystals of new oxyborates, Mg5NbO3(BO3)3 and Mg5TaO3(BO3)3, were synthesized by a self flux method. They crystallize in novel warwickite-type superstructures having ordered arrangements of Mg and Nb/Ta atoms.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Single crystals of two new oxyborates, Mg5NbO3(BO3)3 and Mg5TaO3(BO3)3, were prepared using B2O3 as a flux. ► Both oxyborates crystallize in isotypic novel warwickite-type superstructures with seven-fold coordinated Nb/Ta atoms. ► Polycrystalline sample of Mg5NbO3(BO3)3 was prepared by solid state reaction. ► Polycrystalline Mg5NbO3(BO3)3 exhibits broad blue-to-green emission with a peak wavelength of 470 nm under 270-nm excitation.
