Synthesis and characterization of neptunyl(VI) and plutonyl(VI) orthosilicates
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A.A. Bessonov
Summary
(NpO2)2SiO4·2H2O (I) and (PuO2)2SiO4·2H2O (II) have been prepared by hydrothermal synthesis technique. Chemical composition of (I) was attributed to the compound from its isostructurality with (UO2)2SiO4·2H2O; crystal unit cell parameters of (NpO2)2SiO4·2H2O have been refined as orthorhombic, a=8.365(5)Å, b=11.089(5)Å, c=18.640(9)Å with the space group Fddd. (PuO2)2SiO4·2H2O has not been found isostructural with uranyl(VI) and neptunyl(VI) analogues. Chemical composition of (II) was determined by chemical analysis and proved by the formula volume calculated from powder X-ray data. Indexing of X-ray powder pattern of the prepared compound gave the tetragonal unit cell with a=6.912(3), c=18.563(3)Å, possible space group I41/amd. Visible-near IR and IR absorption spectra of the prepared compounds have been measured in NaCl and KBr. f–f absorption band of PuO22+ in the visible spectrum of crystal (PuO2)2SiO4·2H2O is not splitted but its maximum is essentially shifted (up to 858nm) to the long wave region in comparison with hydrated PuO22+ ions. Visible-near IR absorption spectrum of crystal (NpO2)2SiO4·2H2O is close to that of aqueous neptunyl(VI) solution. Thermal behavior of synthesized compounds has been studied up to 800°C in air.
© 2003 Oldenbourg Wissenschaftsverlag GmbH
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- Uranium speciation in plants
- A fluorescence spectroscopic study on the speciation of Cm(III) and Eu(III) in the presence of organic chelates in highly basic solutions
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- Field study of the migration of 90Sr in a weak loess aquifer
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Artikel in diesem Heft
- The influence of ozone on ligand-assisted extraction of 239Pu and 241Am from Rocky Flats soil
- Biosorption of americium-241 by Candida sp.
- Uranium speciation in plants
- A fluorescence spectroscopic study on the speciation of Cm(III) and Eu(III) in the presence of organic chelates in highly basic solutions
- Synthesis and characterization of neptunyl(VI) and plutonyl(VI) orthosilicates
- Determination of uranium(IV) hydrolysis constants and solubility product of UO2·xH2O
- A comparision of the extraction of carrier-free 176,177W and 99Mo with that of U, Th, Am, Cm, La, Ce, Tm, Yb, Lu and Hf into Aliquat 336 in toluene from nitric, phosphoric, and sulphuric acid media
- Field study of the migration of 90Sr in a weak loess aquifer
- Standardisation of the prompt gamma activation analysis method
