Microstructured layered-kagome BaCo₃(VO₄)₂(OH)₂ with variable crystallite size: alternative synthetic route and comparison with nanostructured samples

Abstract

Microplatelets of the layered-kagome compound BaCo3(VO4)2(OH)2, which is the Co2+ analogue of mineral vesignieite BaCu3(VO4)2(OH)2, have been prepared with very high yield by hydrothermal reaction using synthetic karpenkoite Co3V2O7(OH)2.2H2O as...

Micro- and nanostructured layered-kagome zinc orthovanadate BaZn3(VO4)2(OH)2

“…† The refined crystallite size is of 185(5) nm for BaZn 3 MPs. These results indicate that this compound is isostructural with BaCo 3 (VO 4 ) 2 (OH) 2 , 23,28,30 the crystal structure of An important outcome of our Rietveld refinements is that the average crystal structure is not affected by the synthesis route or by the crystallite size. This can be seen in Tables S2 and S3, ESI, † which gather cell parameters and atom positions for BaZn 3 NPs-7 h and BaZn 3 NPs-25 min, and in Table S4, ESI, † which gives the main interatomic distances for BaZn 3 MPs and for the two nanostructured samples.…”

“…Let us notice that the IR spectra of the BaZn 3 (VO 4 ) 2 (OH) 2 compounds are perfectly comparable with those of the micro-and nanostructured samples of their Co analogues. 28,30 These differences in vibrational spectroscopy signatures between micro-and nanostructured BaM 3 (VO 4 ) 2 (OH) 2 (M = Zn, Co) cannot be explained by differences in the average crystal structures as determined by Rietveld refinements of XRD data.…”

“…Noticeably, the broadening of the Raman peaks increases with decreasing the particle size, indicating that the Raman signature profile of BaZn 3 (VO 4 ) 2 (OH) 2 is strongly impacted by nanostructuring, in perfect agreement with what we recently observed for microand nanostructured BaCo 3 (VO 4 ) 2 (OH) 2 samples. 28,30 High resolution 51 V MAS NMR spectroscopy was also used as a local probe of the crystal structure. Fig.…”

“…28 We reported the synthesis and the magnetic properties of pure quasi-spherical and highly crystalline NPs of BaCo 3 (VO 4 ) 2 (OH) 2 with size in the range of 9-25 nm, by a simple coprecipitation method at ambient pressure, using Ba(CH 3 COO) 2 , Co(NO 3 ) O as a precursor. 30 Strikingly, to the best of our knowledge, the Zn analogue of vesignieite has not been studied so far. Very recently, BaZn 3 (VO 4 ) 2 (OH) 2 has been mentioned as a nonmagnetic reference compound available for evaluating the lattice specific heat of BaNi 3 (VO 4 ) 2 (OH) 2 NPs, 27 but no structural or physicochemical characterisation data have been provided.…”

“…In this work, we report on the synthesis of pure NPs and microplatelets of BaZn 3 (VO 4 ) 2 (OH) 2 using synthetic routes we previously implemented to obtain nano-and microstructured BaCo 3 (VO 4 ) 2 (OH) 2 samples. 28,30 Microplatelets of BaZn 3 (VO 4 ) 2 (OH) 2 (hereafter labelled as BaZn 3 MPs) have been obtained via hydrothermal treatment of Zn 3 V 2 O 7 (OH) 2 •2H 2 O, which is the synthetic analogue of mineral martyite, 6 in Ba (CH 3 COO) 2 aqueous solution. Nanostructured samples with two distinct particle sizes (hereafter labelled as BaZn 3 NPs-25 min and BaZn 3 NPs-7 h) were synthesised, via a coprecipitation method, by varying stirring time.…”