caa a22 4500 37884721X CHVBK 20180305123314.0 cr unu---uuuuu 161128e20030601xx s 000 0 eng 10.1524/ract.91.6.339.20025 doi (NATIONALLICENCE)gruyter-10.1524/ract.91.6.339.20025 Synthesis and characterization of neptunyl(VI) and plutonyl(VI) orthosilicates [Elektronische Daten] [A.A. Bessonov, M.S. Grigoriev, A. B. Ioussov, N.A. Budantseva, A.M. Fedosseev] (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 Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Bessonov A.A. aut Grigoriev M.S. aut Ioussov A. B. aut Budantseva N.A. aut Fedosseev A.M. aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 91/6/2003(2003-06-01), 339-344 0033-8230 91:6/2003<339 2003 91 ract https://doi.org/10.1524/ract.91.6.339.20025 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.91.6.339.20025 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bessonov A.A. aut NATIONALLICENCE 700 1- Grigoriev M.S. aut NATIONALLICENCE 700 1- Ioussov A. B. aut NATIONALLICENCE 700 1- Budantseva N.A. aut NATIONALLICENCE 700 1- Fedosseev A.M. aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 91/6/2003(2003-06-01), 339-344 0033-8230 91:6/2003<339 2003 91 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter