Stoichiometric Mixture Of Eu2O3 Research Articles

Synthesis, Structure, and Thermophysical Properties of EuGaGe2O7

The europium gallium germanate EuGaGe2O7 has been prepared by solid-state reaction in air in the temperature range 1273–1473 K using a stoichiometric mixture of Eu2O3, Ga2O3, and GeO2. Its crystal structure has been determined by X-ray diffraction (sp. gr. P21/c, a = 7.1693(7) A, b = 6.57008(6) A, c = 12.7699(1) A, β = 117.4522(5)°, V = 533.768(8) A3). The heat capacity of polycrystalline samples has been determined by differential scanning calorimetry in the temperature range 350–1053 K and the experimental data have been used to calculate the thermodynamic properties (enthalpy increment, entropy change, and reduced Gibbs energy change) of EuGaGe2O7.

Synthesis and the High-Temperature Heat Capacity Investigation of EuBiGeO5

The EuBiGeO5 compound has been prepared from stoichiometric mixtures of Eu2O3, Bi2O3, and GeO2 by solid-phase synthesis with subsequent multistage annealing in the temperature range of 1003–1223 K. The molar heat capacity of polycrystalline bismuth europium germanate has been determined by differential scanning calorimetry in the temperature range 350–1000 K. The experimental temperature dependence of heat capacity Cp = f(T) contains no anomalies and can be fitted using the Maier–Kelley equation. The key thermodynamic functions of bismuth europium germanate (changes in enthalpy, entropy, and Gibbs free energy) have been calculated.

Synthesis and luminescence spectra of two europium(II) aluminates, EuAl2O4 and EuAl12O19

Two europium(II) aluminates, EuAl2O4 and EuAl12O19, were prepared by a solid-state reaction between europium(III) oxide (Eu2O3) and alumina (Al2O3) powders under a mixed H2 and N2 gas flow. In the preparation of EuAl2O4 from a stoichiometric mixture of Eu2O3 and Al2O3, subtle differences in the products, such as whether the Eu4Al14O25 phase co-occurred or not, were observed between δ- and α-Al2O3 powders, which had an effect on the luminescence spectra. Europium(II) aluminates were formed above 1100°C. A single phase of EuAl2O4 obtained above 1350°C was confirmed by powder X-ray diffraction, infrared spectroscopy, and 27Al magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The 27Al MAS NMR spectrum of EuAl2O4 is reported for the first time. The green emission at 520nm became more intense with increasing calcination temperatures up to 1300°C but diminished at higher temperatures. The EuAl12O19 phosphor was also prepared from a stoichiometric mixture of Eu2O3 and Al2O3 at 1200°C and its luminescence spectrum was compared with that of SrAl12O19:Eu2+.

ChemInform Abstract: Topochemical Synthesis of Europium Molybdenum Oxynitride Pyrochlores.

AbstractEu2Mo2O7 (I) is synthesized from a stoichiometric mixture of Eu2O3, MoO2, and Mo (alumina boat, flowing Ar, 1450 °C, 14 h) and EuMoO4 (II) from a stoichiometric mixture of Eu2O3, MoO3, and Mo (quartz tube, 600 °C, 24 h, and 1050 °C, 36 h).

ChemInform Abstract: A Study on AB2O6 Compounds. Part 1. Synthesis, Structure, Magnetic Properties and 151Eu Moessbauer Spectroscopic Data of EuNb2O6.

AbstractThe title compound is prepared from a stoichiometric mixture of Eu2O3, Nb2O5, and NbO2 (Mo crucible, 1200 °C, 44 h) and characterized by powder XRD, Moessbauer spectroscopy, and magnetic measurements.