Analysis of solid solutions stability in scheelite-type molybdates and tungstates

Журавлев, В. Д.; Резницких, О. Г.; Velikodnyi, Yu. A.; Patrusheva, T. A.; Sivtsova, O. V.

doi:10.1016/j.jssc.2011.08.003

Cited by 14 publications

(5 citation statements)

References 23 publications

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“…Calculated unit cell volumes for all AWO 4 end members compositions are in close agreement with values for bulk materials prepared via high temperature routes. 34 A summary of the calculated structural parameters for the ternary AWO 4 nano-crystals is given in Table 1; structural parameters for all other quaternary compositions and the refined diffraction patterns are provided in the ESI. † The low values for the R wp and χ 2 goodness-of-fit indicators, along with the minimal differences between the least-squares fits and the experimental diffraction patterns, provide further confirmation that the A 1-x A′ x WO 4 nanocrystals are all isostructural and belong to the tetragonal scheelite family.…”

Section: Resultsmentioning

confidence: 99%

Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca_1−xSr_xWO₄ and Sr_1−xBa_xWO₄ nanocrystals

et al. 2015

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A series of compositionally complex scheelite-structured nanocrystals of the formula A1-xAWO4 (A = Ca, Sr, Ba) have been prepared under benign synthesis conditions using the vapor diffusion sol-gel method. Discrete nanocrystals with sub-20 nm mean diameters were obtained after kinetically controlled hydrolysis and polycondensation at room temperature, followed by composition-dependent thermal aging at or below 60 °C. Rietveld analysis of X-ray diffraction data and Raman spectroscopy verified the synthesis of continuous and phase-pure nanocrystal solid solutions across the entire composition space for A1-xAWO4, where 0 ≤ x ≤ 1. Elemental analysis by X-ray photoelectron and inductively coupled plasma-atomic emission spectroscopies demonstrated excellent agreement between the nominal and experimentally determined elemental stoichiometries, while energy dispersive X-ray spectroscopy illustrated good spatial elemental homogeneity within these nanocrystals synthesized under benign conditions.

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Section: Resultsmentioning

confidence: 99%

Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca_1−xSr_xWO₄ and Sr_1−xBa_xWO₄ nanocrystals

et al. 2015

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“…Vesselinov discovered that the morphology of laboratory-grown wulfenite crystals precipitated from an aqueous solution at ambient temperature and atmospheric pressure is influenced by the Pb/Mo concentration ratio. In particular, higher Pb concentrations promote bipyramidal shapes, while higher MoO 2 −4 values favour tabular crystals 12 .…”

Section: Introductionmentioning

confidence: 96%

“…Lower symmetry was proposed to occur in the series of stolzite-wulfenite solid solutions 5 , 9 , 10 , but so far, the minerals in this series have been confirmed to retain space group I4 1 /a 11 . The different morphologies could be due to growth factors, i.e., the growth rates of the crystals depend on the change in the chemical composition of the solutions from which the wulfenite crystals precipitate and the spatial orientation of the crystals during their growth 12 .…”

Section: Introductionmentioning

confidence: 99%

“…Vesselinov 9 , 10 , 12 studied in detail the growth-related morphological diversity of wulfenite crystals by analysing both natural wulfenite samples from the Mežica Mine and laboratory-grown wulfenite crystals. Vesselinov discovered that the morphology of laboratory-grown wulfenite crystals precipitated from an aqueous solution at ambient temperature and atmospheric pressure is influenced by the Pb/Mo concentration ratio.…”

Section: Introductionmentioning

confidence: 99%

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Formation mechanisms and environmental influences on the crystal growth of wulfenite

Gračanin,

Podlogar,

Semsari Parapari

et al. 2024

Sci Rep

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In this study, we introduce a novel approach using correlative analysis techniques to unravel detailed insights into the environmental influences on crystal growth. Tabular and bipyramidal wulfenite samples from the Mežica mine in north-eastern Slovenia were analysed to combine the morphological aspects of crystal growth with the atomic-resolution reconstruction of the positions of lead (Pb) and molybdenum (Mo) atoms in the parent crystal lattice. These combined data also allow us to present the formation mechanism that enables the development of bipyramidal or tabular morphologies in wulfenite. The bipyramidal and tabular crystals are chemically pure wulfenite (PbMoO4), as confirmed by various advanced diffraction and spectroscopy techniques. However, each habit includes multiple inclusions, mostly consisting of carbonates, Pb-Fe oxides, Pb oxides and, more rarely, Pb vanadate (descloizite). The differences in the morphologies can be attributed to compositional changes during precipitation from a meteoric solution and thus, we propose a growth mechanism consisting of three different phases of growth. This innovative approach emphasises the importance of understanding the origin of crystal habits, as can help to decipher how external influences can affect the crystal structure and its surface, leading to the dissolution of preferred surfaces and the selective release of Pb and Mo.

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“…Hetrostructcured metal oxides constituting molybdates, tungstate and vanadates are important families that exhibit narrow band gap for harvesting solar light for catalysis. Molybdates adopt tetrahedral coordination with relative large bivalent cations; (Sr, Pb, Ba and Ca) ionic radius (>0.99 A) and exists in Scheelite type structure and have relative ionic radius (<0.77 Å) with bivalent cation (Co, Ni, Mg, Mn, Zn) and overall, it adopt six-fold coordinated octahedral geometry and constitute Wolframite geometry [45]. Previously, iron molybdate shown promising efficiency as photocatalyst for the removal of endosulfan, heptachlor and Rhodamine B dye and the efficiency was reported to be very promising [28,[46][47][48][49].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization and photocatalytic performance of iron molybdate (Fe₂(MoO₄)₃) for the degradation of endosulfan pesticide

Parveen

Bhatti

Ashar

et al. 2020

Mater. Res. Express

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Iron molybdate was prepared via simple solution chemistry method and the photocatalytic degradation of a pesticide (endosulfan) was investigated under visible light irradiation. As-prepared (Fe 2 (MoO 4 ) 3 ) was characterized using scanning electron microscope (SEM), x-ray diffraction (XRD), energy dispersive x-ray spectra (EDX), diffused reflectance spectroscopy (DRS) and Zeta particle sizer techniques. The iron molybdate crystallite size was 36 nm, while grain size was in the range of 160-340 nm. The particles of polymetallic compound were spherical, highly porous and with fluffy texture indicating high surface area. DRS revealed Fe 2 (MoO 4 ) 3 was active under visible region since band gap value calculated was 2.7 eV. Response surface methodology (RSM) was employed for the optimization of photocatalytic activity (PCA) of Fe 2 (MoO 4 ) 3 as a function of catalyst dose, H 2 O 2 dose, solution pH and concentration of endosulfan and up to 77% degradation was achieved at optimum conditions, which was monitored by UV/vis spectroscopy. In response to endosulfan degradation, the chemical oxygen demand (COD) and total organic carbon (TOC) were reduced up to 76% and 67%, respectively. Results revealed that iron molybdate is highly efficient photocatalyst for the degradation of endosulfan under solar light irradiation and could possibly be used for the treatment of endosulfan containing wastewater.

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Analysis of solid solutions stability in scheelite-type molybdates and tungstates

Cited by 14 publications

References 23 publications

Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca_1−xSr_xWO₄ and Sr_1−xBa_xWO₄ nanocrystals

Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca_1−xSr_xWO₄ and Sr_1−xBa_xWO₄ nanocrystals

Formation mechanisms and environmental influences on the crystal growth of wulfenite

Synthesis, characterization and photocatalytic performance of iron molybdate (Fe₂(MoO₄)₃) for the degradation of endosulfan pesticide

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Analysis of solid solutions stability in scheelite-type molybdates and tungstates

Cited by 14 publications

References 23 publications

Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca1−xSrxWO4 and Sr1−xBaxWO4 nanocrystals

Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca1−xSrxWO4 and Sr1−xBaxWO4 nanocrystals

Formation mechanisms and environmental influences on the crystal growth of wulfenite

Synthesis, characterization and photocatalytic performance of iron molybdate (Fe2(MoO4)3) for the degradation of endosulfan pesticide

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Product

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Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca_1−xSr_xWO₄ and Sr_1−xBa_xWO₄ nanocrystals

Low-temperature synthesis of homogeneous solid solutions of scheelite-structured Ca_1−xSr_xWO₄ and Sr_1−xBa_xWO₄ nanocrystals

Synthesis, characterization and photocatalytic performance of iron molybdate (Fe₂(MoO₄)₃) for the degradation of endosulfan pesticide