Structure and stability of monazite- and zircon-type LaVO4 under hydrostatic pressure

Cheng, Xuerui; Guo, Dongjie; Feng, Shiquan; Yang, Kun; Wang, Yongqiang; Ren, Yufen; Song, Yang

doi:10.1016/j.optmat.2015.08.011

Cited by 34 publications

(48 citation statements)

References 36 publications

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“…Therefore, on the light of the exposed results we are confident that the second HP phase of NdVO4 is the BaWO4-II structure. Furthermore, the monazite-BaWO4-II phase transition is consistent with Bastide's diagram [8] because in some materials the monazitescheelite phase transition can be skipped and undergo a phase transition directly to a post-scheelite phase, as evidenced in PbWO4 and BaWO4 [50 -53]. Additionally, monazite LaVO4 has been recently reported to undergo a monazite-BaWO4-II transition [48], which suggests that the BaWO4-II structure might be a common post-monazite phase in AVO4 vanadates if the trivalent cation has a large ionic radius (La, Ce, Nd, and Pr).…”

Section: Post-monazite Phasesupporting

confidence: 78%

“…Therefore, we think there is enough evidence to support the existence of a postmonazite phase in NdVO4. In a previous work, a tentative phase transition to the scheelite phase was proposed [27]; however, in this work we have carried out calculations for a larger number of candidate structures on the light of the Bastide's diagram [8]. Our improved calculations suggest the possibility that the post-monazite phase in NdVO4 is of BaWO4-II-type.…”

Section: Post-monazite Phasementioning

confidence: 87%

“…Rare-earth AVO4 orthovanadates (A = Sc, Y, La -Lu) mostly crystallize in the tetragonal zircon-type structure (space group I41/amd) [7], although it has been found that a few orthovanadates (e.g. LaVO4) crystallize in the monazite structure (space group P21/n), depending on the synthesis conditions and cationic size [8]. Another structure which is closely related to zircon and monazite structures is the scheelite (space group I41/a) structure.…”

Section: Introductionmentioning

confidence: 99%

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High-pressure lattice-dynamics of NdVO4

Panchal¹,

Errandonea

Manjón

et al. 2017

Journal of Physics and Chemistry of Solids

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High-pressure Raman-scattering measurements and ab initio calculations on NdVO4 have been carried out up to 30 GPa. Our combined experimental and theoretical study confirms that beyond 5.9 GPa NdVO4 undergoes an irreversible zircon to monazite transition. The coexistence of zircon and monazite phases is experimentally observed up to ~ 8 GPa (which agrees with the theoretical transition pressure), stabilizing the monazite phase as a single phase around 10 GPa. Calculations additionally predict the existence of a second high-pressure phase transition at 12.4 GPa. This reversible phase transition has been experimentally observed beyond 18.1 GPa and remains stable up to 30 GPa. The post-monazite phase is predicted to have a monoclinic structure isomorphic to the BaWO4-II type structure. The calculated structure for the three polymorphs of NdVO4 is reported and the pressure dependence of their Raman modes is discussed.

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Section: Post-monazite Phasesupporting

confidence: 78%

Section: Post-monazite Phasementioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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High-pressure lattice-dynamics of NdVO4

Panchal¹,

Errandonea

Manjón

et al. 2017

Journal of Physics and Chemistry of Solids

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“…The most widely used photocatalyst TiO 2 is only active under ultraviolet light irradiation [2,3]. Europium (EuVO 4 ) [4] and lanthanum (LaVO 4 ) [5] vanadates are of special interest, since they are among the most promising visible-light-driven photocatalysts [6]. These compounds also offer chemical stability and non-toxicity.…”

Section: Introductionmentioning

confidence: 99%

“…There exist different methods to obtain vanadate particles, such as solid-state or [9] hydrothermal synthesis [5], sol-gel method [10], etc. One of the most promising ways to obtain excellent homogenization at the atomic scale and high reactivity, is the sol-gel method.…”

Section: Introductionmentioning

confidence: 99%

Preparation, structure and luminescence properties of the Ln1-xCaxVO4, Ln = La, Eu (0 ≤ x ≤ 0.2) phases

Slepets¹,

Voitenko²,

Nedilko³

et al. 2016

Chem. Met. Alloys

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Ln 1-x Ca x VO 4 , Ln = La, Eu (0 ≤ x ≤ 0.2) samples were prepared by the aqueous nitrate-citrate sol-gel route using citric acid as complexing agent. Thermal analysis was used to explain the thermal decomposition behavior and crystallization process of the Eu 0.9 Ca 0.1 VO 4 sample. Single-phase samples of the investigated compounds formed at 630°C. According to X-ray diffraction data, a monoclinic phase of Ca 2+-doped LaVO 4 and a tetragonal phase of Ca 2+-doped EuVO 4 nanoparticles were obtained. Scanning electron microscopy images showed particles of different shapes with diameters from 100 to 500 nm, the crystallite surface being loose and porous. The photoluminescence spectra contain wide bands of matrix emission and narrow lines due to f-f transitions in the Ln 3+ ions. Ca 2+-doped RVO 4 / Nanoparticles / Sol-gel process / Thermal analysis / Scanning electron microscopy SEM

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A systematic study of rare‐earth ions size‐dependent structural phase transition from monazite to zircon‐type in rare earth chromates using Raman spectroscopy

Ughade

Poddar

2023

J Raman Spectroscopy

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Rare earth chromates (RCrO 4 ) undergo monazite to zircon-type structural phase transition due to a decreased rare-earth ion size. They also exhibit an intermediate mixed phase. However, there is no systematic study on the influence of structural distortion on their phononic behavior, which is quite sensitive to subtle environmental variations. A change in the room temperature phononic spectrum was studied in the family of RCrO 4 compounds, where R was varied from La to Yb using Raman modes. With an increase in the atomic number from Nd to Yb for zircon-type phases, the external translational and rotational modes were observed to shift towards lower and higher wavenumbers, respectively. At the same time, all internal vibrational modes shifted towards higher phonon energies. A comparison between Raman modes for monazite, intermediate, and zircon-type RCrO 4 phases showed a gradual shift in the internal modes towards a higher wavenumber. The confirmation of the change in Raman modes with the decreasing radius was found by comparing the rare-earth elements in DyCrO 4 and LaCrO 4 with non-rare-earth elements in YCrO 4 . K E Y W O R D Smonazite-type, Raman spectroscopy, rare earth chromates (RCrO 4 ), YCrO 4 , zircon type

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Structure and stability of monazite- and zircon-type LaVO4 under hydrostatic pressure

Cited by 34 publications

References 36 publications

High-pressure lattice-dynamics of NdVO4

High-pressure lattice-dynamics of NdVO4

Preparation, structure and luminescence properties of the Ln1-xCaxVO4, Ln = La, Eu (0 ≤ x ≤ 0.2) phases

A systematic study of rare‐earth ions size‐dependent structural phase transition from monazite to zircon‐type in rare earth chromates using Raman spectroscopy

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