Micro- and nanostructured layered-kagome zinc orthovanadate BaZn(VO)(OH).

Pure micro- and nanocrystalline powders of the layered-kagome zinc orthovanadate BaZn(VO)(OH) have been successfully prepared and thoroughly characterised. Microstructured samples (BaZn3-MPs) have been produced by hydrothermal reaction using synthetic martyite ZnVO(OH)·2HO as the starting reagent. Nanoparticles (NPs) with an average size of ≈ 60 nm (BaZn3-NPs-7h) or ≈ 50 nm (BaZn3-NPs-25min) have been obtained by using a coprecipitation method at ambient pressure, and by varying the stirring time.

Microstructured layered-kagome BaCo(VO)(OH) with variable crystallite size: alternative synthetic route and comparison with nanostructured samples.

Microplatelets of the layered-kagome compound BaCo(VO)(OH), which is the Co analogue of mineral vesignieite BaCu(VO)(OH), have been prepared with very high yield by hydrothermal reaction using synthetic karpenkoite CoVO(OH)·2HO as starting reagent. The Rietveld refinement of X-ray diffraction data indicates that CoVO(OH)·2HO is isostructural with martyite ZnVO(OH)·2HO. Two single-phased samples of microstructured BaCo(VO)(OH) have been characterized using powder X-ray diffraction, FT-IR and Raman spectroscopies, thermal analyses, scanning electron microscopy, energy-dispersive X-ray spectroscopy and magnetisation measurements.