Oxide pyrochlores — A review

Total reflection X-ray fluorescence (TXRF)-based X-ray absorption near-edge spectroscopy has been used to determine the oxidation state of uranium in mixed-valent U3O8 and U3O7 uranium oxides. The TXRF spectra of the compounds were measured using variable X-ray energies in the vicinity of the U L3 edge in the TXRF excitation mode at the microfocus beamline of the Indus-2 synchrotron facility. The TXRF-based X-ray absorption near-edge spectroscopy (TXRF-XANES) spectra were deduced from the emission spectra measured using the energies below and above the U L3 edge in the XANES region. The data processing using TXRF-XANES spectra of U(IV), U(V), and U(VI) standard compounds revealed that U present in U3O8 is a mixture of U(V) and U(VI), whereas U in U3O7 is mixture of U(IV) and U(VI). The results obtained in this study are similar to that reported in literature using the U M edge. The present study has demonstrated the possibility of application of TXRF for the oxidation state determination and elemental spe...

Direct Determination of Oxidation States of Uranium in Mixed-Valent Uranium Oxides Using Total Reflection X-ray Fluorescence X-ray Absorption Near-Edge Spectroscopy

A comprehensive analysis of X-ray absorption data obtained at the U L3-edge for a systematic series of single-valence (UO2, KUO3, UO3) and mixed-valence uranium compounds (U4O9, U3O7, U3O8) is repo...

Local Structure in U(IV) and U(V) Environments: The Case of U3O7

Powder neutron diffraction data have been recorded for KUO3. Rietveld refinement confirms that the compound adopts a regular perovskite structure [space group Pm3m, a= 4.29601(2)A] with regular UO6 octahedra.

Powder neutron diffraction study of potassium uranate(V), KUO3

M2U4O12 compounds of potassium, rubidium and thallium

Reduction of thallium(I) uranates(VI) by diverse methods led to formation of only one thallium(I) uranate(V), namely, T1UO3. T1UO3 unlike KUO3 exhibits the pyrochlore structure. Its physical and chemical characteristics were examined and rationalised.



Thallium (I)-uranat(V)



Die Reduktion von Thallium(I)-uranaten(VI) fuhrst stets nur zu einem einzigen Thallium(I)-uranat(V), namlich T1UO3. Im Gegensatz zu KUO3 Pyrochlorstruktur. Seine physikalischen und chemischen Eigenschaften werden beschrieben.

Thallium(I) Uranate(V)

Telluride ion forms polynuclear soluble cationic complexes with excess Hg(II) in sulphuric acid media. Compounds Hg5TeCl8 and Hg4Te(SO4)3 were prepared and characterised.



Darstellung und Eigenschaften von Hg5TeCl8



In schwefelsaurer Losung reagiert HgTe mit uberschussigen Quecksilber(II)-Ionen unter Bildung loslicher kationischer mehrkerniger Komplexe. Die Verbindungen Hg5TeCl8 und Hg4Te(SO4)3 werden dargestellt und beschrieben.

N. Ramadass

Papers

Thallium(I) Uranate(V)

Preparation and characterization of a novel mercury(II) telluride chloride Hg5TeCl8

Preparation and characterization of a novel mercury(ii) telluride chloride hg5tecl8

Thallium(i) uranate(v)