RbEu(MoO4)2 is synthesized by the two-step solid state reaction method. The crystal structure of RbEu(MoO4)2 is defined by Rietveld analysis in space group Pbcn with cell parameters a = 5.13502(5), ...b = 18.8581(2) and c = 8.12849(7) Å, V = 787.13(1) Å3, Z = 4 (RB = 0.86%). This molybdate possesses its phase transition at 817 K and melts at 1250 K. The Raman spectra were measured with the excitation at λ = 1064 and 514.5 nm. The photoluminescence spectrum is evaluated under the excitation at 514.5 nm. The absolute domination of hypersensitive 5D0→7F2 transition is observed. The ultranarrow 5D0→7F0 transition in RbEu(MoO4)2 is positioned at 580.2 nm being 0.2 nm blue shifted, with respect to that in Eu2(MoO4)3.
•RbEu(MoO4)2 is synthesized by the two-step solid state reaction method.•The crystal structure of RbEu(MoO4)2 is defined by Rietveld analysis in space group Pbcn.•The absolute domination of hypersensitive 5D0.→7F2 transition is observed.
The powder α-Eu2(MoO4)3 sample was prepared by the solid-state reaction method. The phase purity of the final powder product was verified by X-ray diffraction analysis. The constituent element core ...levels and valence band are measured by X-ray photoelectron spectroscopy as a function of Ar+ ion (2.5 keV, 7–8 μA/cm2) bombardment time. The formation of Mo5+ and Mo4+ states at high bombardment times was detected. The Eu–O and Mo–O bonding was considered in comparison with other Eu3+- and Mo6+-containing oxides using binding energy difference parameters. The transparency range obtained for the pure α-Eu2(MoO4)3 tablet is λ = 0.41–0.97 μm, as estimated at the transmission level of 5%. The short-wavelength cut edge in α-Eu2(MoO4)3 is governed by the direct allowed optical transitions within the band gap of E g = 3.74 eV (300 K). The band structure of α-Eu2(MoO4)3 was calculated by ab initio methods and strongly different results were obtained for the spin up/down configurations. The Eu-4f states are located around 2.2 eV and −4.0 eV for spin up (↑) and the structures situated at around 6.5 and 5.5 eV for spin down (↓) configuration. The calculated spin magnetic moments are in excellent relation to the Slater-Pauling rule and within the Eu sphere the magnetic moment of 4f electrons is ∼5.99 μB.
In the present work, we report on the synthesis of EuSO4 powders by two different methods using EuS as starting material. The compound EuSO4 contains divalent europium and crystallizes in the ...orthorhombic crystal system, space group Pnma with parameters close to SrSO4. The compound exhibits near isotropic thermal expansion over the temperature range 300–700 K. EuSO4 was examined by Raman, Fourier‐transform infrared absorption and luminescence spectroscopy methods. EuSO4 is found to be an indirect bandgap material with a bandgap close to direct electronic transition. The emission lifetime of divalent europium d‐f emission in EuSO4 shows an unusual behavior for stoichiometric compounds, as it shortens upon cooling from 1.11(1) μs at room temperature to 0.44(1) μs at 77 K.
Efficient methods for the synthesis of europium (II) sulfate in various dimensional states based on exchange reactions have been developed. The crystal structure of the compound is determined and its relationship with the main thermochemical and optical properties is shown.
Abstract
In the present work, we report on the synthesis of EuSO
4
powders by two different methods using EuS as starting material. The compound EuSO
4
contains divalent europium and crystallizes in ...the orthorhombic crystal system, space group
P
nma
with parameters close to SrSO
4
. The compound exhibits near isotropic thermal expansion over the temperature range 300–700 K. EuSO
4
was examined by Raman, Fourier‐transform infrared absorption and luminescence spectroscopy methods. EuSO
4
is found to be an indirect bandgap material with a bandgap close to direct electronic transition. The emission lifetime of divalent europium
d‐f
emission in EuSO
4
shows an unusual behavior for stoichiometric compounds, as it shortens upon cooling from 1.11(1) μs at room temperature to 0.44(1) μs at 77 K.
Rubidium neodymium molybdate, RbN(MoO 4 ) 2 has been synthesized by solid state reaction at T = 350°-600°C for 50 h in air. Morphology of RbNd(MoO 4 ) 2 micrograins has been observed with SEM. Phase ...purity of final product is confirmed with XRD analysis. Crystal structure related to KY(MoO 4 ) 2 -type, space group Pbcn, is supposed by XRD pattern comparison.
Microcrystals of MNd(MoO 4 ) 2 (M=Rb, Tl) and TlPr(MoO 4 ) 2 have been formed with solid state synthesis by the same synthesis route. Final products have been studied by XRD and SEM. Vibrational ...properties have been evaluated with Raman spectroscopy. More than 20 narrow Raman lines were observed in the experimental spectrum of the microcrystals.
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