Browse
Submit Data
Databases
API
Help

Dataset Information

24 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Two new glaserite-type orthovanadates: Rb₂KDy(VO₄)₂ and Cs_1.52K_1.48Gd(VO₄)₂.

ABSTRACT: The crystal structures of dirubidium potassium dysprosium bis-(vanadate), Rb₂KDy(VO₄)₂, and caesium potassium gadolinium bis-(vanadate), Cs_1.52K_1.48Gd(VO₄)₂, were solved from single-crystal X-ray diffraction data. Both compounds, synthesized by the reactive flux method, crystallize in the space group P m1 with the glaserite structure type. VO₄ tetra-hedra are linked to DyO₆ or GdO₆ octa-hedra by common vertices to form sheets stacking along the c axis. The large twelve-coordinate Cs⁺ or Rb⁺ cations are sandwiched between these layers in tunnels along the a and b axes, while the K⁺ cations, surrounded by ten oxygen atoms, are localized in cavities.

SUBMITTER: Rghioui L

PROVIDER: S-EPMC6659331 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Two new glaserite-type orthovanadates: Rb2KDy(VO4)2 and Cs1.52K1.48Gd(VO4)2.

Rghioui Lotfi L El Ammari Lahcen L Assani Abderrazzak A Saadi Mohamed M

Acta crystallographica. Section E, Crystallographic communications 20190621 Pt 7

The crystal structures of dirubidium potassium dysprosium bis-(vanadate), Rb2KDy(VO4)2, and caesium potassium gadolinium bis-(vanadate), Cs1.52K1.48Gd(VO4)2, were solved from single-crystal X-ray diffraction data. Both compounds, synthesized by the reactive flux method, crystallize in the space group P m1 with the glaserite structure type. VO4 tetra-hedra are linked to DyO6 or GdO<sub ...[more]

PMID: 31392021

Similar Datasets

MIn(HAsO4)2 (M = K, Rb, Cs): three new hydrogen-arsenates adopting two different structure types.

Project description:Potassium indium bis-[hydrogen arsenate(V)], KIn(HAsO4)2, rubidium indium bis-[hydrogen arsenate(V)], RbIn(HAsO4)2, and caesium indium bis-[hydrogen arsenate(V)], CsIn(HAsO4)2, were grown under mild hydro-thermal conditions (T = 493 K, 7-8 d). KIn(HAsO4)2 adopts the KSc(HAsO4)2 structure type (space group C2/c), while RbIn(HAsO4)2 and CsIn(HAsO4)2 crystallize in the space group R-3c and are the first arsenate representatives of the RbFe(HPO4)2 structure type. All three compounds have tetra-hedral-octa-hedral framework topologies. The M+ cations, located in voids of the respective framework, are slightly disordered in RbIn(HAsO4)2. In KIn(HAsO4)2, there is a second K-atom position with a very low occupancy, which may suggest that the K atom can easily move in the channels extending along [101].

| S-EPMC5730323 | biostudies-literature

Growth, Properties, and Theoretical Analysis of M2LiVO4 (M = Rb, Cs) Crystals: Two Potential Mid-Infrared Nonlinear Optical Materials.

Project description:Mid-Infrared nonlinear optical (Mid-IR NLO) crystals with excellent performances play a particularly important role for applications in areas such as telecommunications, laser guidance, and explosives detection. However, the design and growth of high performance Mid-IR NLO crystals with large NLO efficiency and high laser-damage threshold (LDT) still face numerous fundamental challenge. In this study, two potential Mid-IR NLO materials, Rb2LiVO4 (RLVO) and Cs2LiVO4 (CLVO) with noncentrosymmetric structures (Orthorhombic, Cmc21) were synthesized by high-temperature solution method. Thermal analysis and powder X-ray diffraction demonstrate that RLVO and CLVO melt congruently. Centimeter sized crystals of CLVO have been grown by the top-seeded solution growth method. RLVO and CLVO exhibit strong second harmonic generation (SHG) effects (about 4 and 5 times that of KH2PO4, respectively) with a phase-matching behavior at 1.064 μm, and a wide transparency range (0.33-6.0 μm for CLVO). More importantly, RLVO and CLVO possess a high LDT value (~28 × AgGaS2). In addition, the density functional theory (DFT) and dipole moments studies indicate that the VO4 anionic groups have a dominant contribution to the SHG effects in RLVO and CLVO. These results suggest that the title compounds are promising NLO candidate crystals applied in the Mid-IR region.

| S-EPMC5432528 | biostudies-literature

Rb/Cs-Modified P2 Na0.7Mn0.8Mg0.2O2: Application in Sodium-Ion Batteries.

Project description:To meet the growing energy demands, sodium-ion batteries can be a potential substitute for lithium-ion batteries. Here, we report the solid-state synthesized alkali Rb- and Cs-modified Na0.7Mn0.8Mg0.2O2, which adopts hexagonal P63/mmc symmetry. The second charge/discharge capacity for the as-synthesized Rb- and Cs-modified P2 Na0.7Mn0.8Mg0.2O2 are 118/114 and 130/125 mA h g-1, which reduces to 62/62 and 77/76 mA h g-1, respectively, after 100 cycles. In situ synchrotron X-ray diffraction data illustrate that a solid solution reaction occurs for most of the charge/discharge process in both cases. Rb-modified P2 Na0.7Mn0.8Mg0.2O2 shows multiple phases near the charged state, whereas Cs-modified P2 Na0.7Mn0.8Mg0.2O2 shows the formation of a new phase (P2new) at about 2.5 V and multiple phases below 1.7 V. The P2new phase is found to evolve in conjunction with the original P2 phase until about 1.7 V, where the P2 reflection appears to split into multiple reflections and a single P2 phase is recovered at 2.7 V on the second charge. The Cs-modified P2 Na0.7Mn0.8Mg0.2O2 shows better energy density in comparison with the K- and Rb-modified P2 Na0.7Mn0.8Mg0.2O2 and comparable to the parent P2 Na0.7Mn0.8Mg0.2O2. Ex situ scanning electron microscopy images show no noticeable change in surface morphology of the Cs-modified Na0.7Mn0.8Mg0.2O2, whereas in the case of Rb-modified P2 Na0.7Mn0.8Mg0.2O2, rods and irregular-shaped particles are observed after the 100th cycle. The solid-state 23Na NMR shows a distinct shift in the peak position in comparison with the parent P2 Na0.7Mn0.8Mg0.2O2, and two Na environments are observed with no local disordering in Rb- and Cs-modified P2 Na0.7Mn0.8Mg0.2O2 samples. Overall, this article illustrates the influence of using larger alkali ions to modify P2 Na0.7Mn0.8Mg0.2O2 and compares this scheme in terms of phase transitions and electrochemical performance.

| S-EPMC6648630 | biostudies-literature

Two new Rb-Ga arsenates: RbGa(HAsO4)2 and RbGa2As(HAsO4)6.

Project description:The crystal structures of hydro-thermally synthesized (T = 493?K, 7-9?d) rubidium gallium bis-[hydrogenarsenate(V)], RbGa(HAsO4)2, and rubidium digallium arsenic(V) hexa-[hydrogenarsenate(V)], RbGa2As(HAsO4)6, were solved by single-crystal X-ray diffraction. Both compounds have tetra-hedral-octa-hedral framework topologies. The M+ cations are located in channels of the respective framework. RbGa(HAsO4)2 crystallizes in the RbFe(HPO4)2 structure type (Rc), while RbGa2As(HAsO4)6 adopts the structure type of RbAl2As(HAsO4)6 (Rc), which represents a modification of the RbFe(HPO4)2 structure type. In this modification, one third of the M3+O6 octa-hedra are replaced by AsO6 octa-hedra, and two thirds of the voids in the structure, which are usually filled by M+ cations, remain empty to achieve charge balance.

| S-EPMC6127722 | biostudies-literature

Syntheses and crystal structures of a new family of hybrid perovskites: C5H14N2·ABr3·0.5H2O (A = K, Rb, Cs).

Project description:The syntheses and crystal structures of three hybrid perovskites, viz. poly[1-methyl-piperizine-1,4-diium [tri-μ-bromido-potassium] hemihydrate], {(C5H14N2)[KBr3]·0.5H2O} n , (I), poly[1-methyl-piperizine-1,4-diium [tri-μ-bromido-rubidium] hemihydrate], {(C5H14N2)[RbBr3]·0.5H2O} n , (II), and poly[1-methyl-piperizine-1,4-diium [tri-μ-bromido-caesium] hemihydrate], {(C5H14N2)[CsBr3]·0.5H2O} n , (III), are described. These isostructural (space group Amm2) phases contain a three-dimensional, corner-sharing network of distorted ABr6 octa-hedra (A = K, Rb, Cs) with the same topology as the classical perovskite structure. The doubly protonated C5H14N2 2+ cations occupy inter-stices bounded by eight octa-hedra and the water mol-ecules lie in square sites bounded by four octa-hedra. N-H⋯Br, N-H⋯(Br,Br), N-H⋯O and O-H⋯Br hydrogen bonds consolidate the structures.

| S-EPMC6690442 | biostudies-literature

Tunable resistivity of correlated VO2(A) and VO2(B) via tungsten doping.

Project description:Applications of correlated vanadium dioxides VO2(A) and VO2(B) in electrical devices are limited due to the lack of effective methods for tuning their fundamental properties. We find that the resistivity of VO2(A) and VO2(B) is widely tunable by doping them with tungsten ions. When x < 0.1 in V1-xWxO2(A), the resistivity decreases drastically by four orders of magnitude with increasing x, while that of V1-xWxO2(B) shows the opposite behaviour. Using spectroscopic ellipsometry and X-ray photoemission spectroscopy, we propose that correlation effects are modulated by either chemical-strain-induced redistribution of V-V distances or electron-doping-induced band filling in V1-xWxO2(A), while electron scattering induced by disorder plays a more dominant role in V1-xWxO2(B). The tunable resistivity makes correlated VO2(A) and VO2(B) appealing for next-generation electronic devices.

| S-EPMC7297976 | biostudies-literature

Phase Segregation in Cs-, Rb- and K-Doped Mixed-Cation (MA)x(FA)1-xPbI3 Hybrid Perovskites from Solid-State NMR.

Project description:Hybrid (organic-inorganic) multication lead halide perovskites hold promise for a new generation of easily processable solar cells. Best performing compositions to date are multiple-cation solid alloys of formamidinium (FA), methylammonium (MA), cesium, and rubidium lead halides which provide power conversion efficiencies up to around 22%. Here, we elucidate the atomic-level nature of Cs and Rb incorporation into the perovskite lattice of FA-based materials. We use 133Cs, 87Rb, 39K, 13C, and 14N solid-state MAS NMR to probe microscopic composition of Cs-, Rb-, K-, MA-, and FA-containing phases in double-, triple-, and quadruple-cation lead halides in bulk and in a thin film. Contrary to previous reports, we have found no proof of Rb or K incorporation into the 3D perovskite lattice in these systems. We also show that the structure of bulk mechanochemical perovskites bears close resemblance to that of thin films, making them a good benchmark for structural studies. These findings provide fundamental understanding of previously reported excellent photovoltaic parameters in these systems and their superior stability.

| S-EPMC5719467 | biostudies-literature

A New Fitness Test of Estimating VO2max in Well-Trained Rowing Athletes.

Project description:BackgroundThis study was designed to investigate the validity of maximal oxygen consumption (VO2max) estimation through the Firstbeat fitness test (FFT) method when using submaximal rowing and running programs for well-trained athletes.MethodsWell-trained flatwater rowers (n = 45, 19.8 ± 3.0 years, 184 ± 8.7 cm, 76 ± 12.9 kg, and 58.7 ± 6.0 mL⋅kg-1⋅min-1) and paddlers (n = 45, 19.0 ± 2.5 years, 180 ± 7.7 cm, 74 ± 9.4 kg, and 59.9 ± 4.8 mL⋅kg-1⋅min-1) completed the FFT and maximal graded exercise test (GXT) programs of rowing and running, respectively. The estimated VO2max was calculated using the FFT system, and the measured VO2max was obtained from the GXT programs. Differences between the estimated and measured VO2max values were analyzed to assess the accuracy and agreement of the predictions. Equations from the previous study were also used to predict the VO2max in the submaximal programs to compare the accuracy of prediction with the FFT method.ResultsThe FFT method was in good agreement with the measured VO2max in both groups based on the intraclass correlation coefficients (>0.8). Additionally, the FFT method had considerable accuracy in VO2max estimation as the mean absolute percentage error (≤5.0%) and mean absolute error (<3.0 mL⋅kg-1⋅min-1) were fairly low. Furthermore, the FFT method seemed more accurate in the estimation of VO2max than previously reported equations, especially in the rowing test program.ConclusionThis study revealed that the FFT method provides a considerably accurate estimation of VO2max in well-trained athletes.

| S-EPMC8283806 | biostudies-literature

Two Mercury Antimony Chalcogenides Cs2HgSb4S8 and Cs2Hg2Sb2Se6 with Cesium Cations as Counterions.

Project description:Two novel layer structure compounds, Cs2HgSb4S8 and Cs2Hg2Sb2Se6, were synthesized in organic solvent under solvothermal conditions. The Cs2HgSb4S8 is formed of [HgSb4S8]2- ribbons and S atoms by corner sharing. The Cs2Hg2Sb2Se6 is made up of [SbHg2Se6]5- ribbon and disorder trigonal-pyramidal SbSe3 by sharing μ3-Se. These compounds are characterized by single-crystal X-ray diffraction, powder X-ray diffraction, solid-state optical absorption spectra, and so on.

| S-EPMC6643381 | biostudies-literature

Structural characterization of quaternary selenites of tungsten(VI), A 2W3SeO12 (A = NH4, Cs, Rb, K or Tl).

Project description:The quaternary A 2W3SeO12 (A = NH4, Cs, Rb, K or Tl) selenites have been prepared in the form of single crystals by hydro-thermal and novel solid-state reactions. They were characterized by X-ray diffraction, thermal and spectroscopic studies. All of them have a hexa-gonal tungsten oxide (HTO) related [W3SeO12]2- anionic framework with pyramidally coordinated Se4+ ions. The known A 2W3SeO12 (A = NH4, Cs or Rb) compounds are isostructural with the Cs2W3TeO12 compound and have a non-centrosymmetric layered structure containing intra-layer Se-O bonds. The new compound K2W3SeO12(α) is isostructural with the K2W3TeO12 compound and has a centrosymmetric three-dimensional structure containing inter-layer Se-O bonds. It is inferred that the new Tl2W3SeO12 compound has the same three-dimensional structure as K2W3SeO12(α).

| S-EPMC8025859 | biostudies-literature