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Titolo:
LOW-TEMPERATURE CRYSTAL-STRUCTURES AND THERMAL-DECOMPOSITION OF URANYL HYDROGEN SELENITE MONOHYDRATE, UO2(HSEO3)(2) H2O AND DIAMMONIUM URANYL SELENITE HEMIHYDRATE, (NH4)(2)UO2(SEO3)(2)CENTER-DOT-0.5H(2)O
Autore:
KOSKENLINNA M; MUTIKAINEN I; LESKELA T; LESKELA M;
Indirizzi:
UNIV HELSINKI,DEPT CHEM,POB 55 FIN-00014 HELSINKI FINLAND UNIV HELSINKI,DEPT CHEM FIN-00014 HELSINKI FINLAND TECHNOL DEV CTR FIN-00101 HELSINKI FINLAND HELSINKI UNIV TECHNOL,INORGAN & ANALYT CHEM LAB FIN-02150 ESPOO FINLAND
Titolo Testata:
Acta chemica Scandinavica
fascicolo: 3, volume: 51, anno: 1997,
pagine: 264 - 269
SICI:
0904-213X(1997)51:3<264:LCATOU>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
DISELENITE; UO2SE2O5;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
22
Recensione:
Indirizzi per estratti:
Citazione:
M. Koskenlinna et al., "LOW-TEMPERATURE CRYSTAL-STRUCTURES AND THERMAL-DECOMPOSITION OF URANYL HYDROGEN SELENITE MONOHYDRATE, UO2(HSEO3)(2) H2O AND DIAMMONIUM URANYL SELENITE HEMIHYDRATE, (NH4)(2)UO2(SEO3)(2)CENTER-DOT-0.5H(2)O", Acta chemica Scandinavica, 51(3), 1997, pp. 264-269

Abstract

The structures of the uranyl hydrogen selenite monohydrate, UO2(HSeO3)(2) . H2O and diammonium uranyl selenite hemihydrate, (NH4)(2)UO2(SeO3)(2) . 0.5H(2)O have been determined by S-ray diffraction at 193 K and their thermal decomposition studied. The structure of (NH4)(2)UO2(SeO3)(2) . 0.5H(2)O is layered. The layers are formed by the two unequalselenite ions acting as bridging ligands between three and two U-VI ions, respectively. The ammonium ions and the water molecule form an array, which through a complex hydrogen bond network holds the layers together. In UO2(HSeO3)(2) . H2O the hydrogen selenite ion acts as a bridging ligand between two consecutive U-VI ions, leading to a structureof one-dimensional zigzag chains. (NH4)(2)UO2(SeO3)(2) . 0.5H(2)O decomposes in air between 570 and 640 K in a single thermogravimetric step to a phase containing uranyl selenite with additional selenium dioxide. The final product, U3O8, is formed between 870 and 930 K. After dehydration UO2(HSeO3)(2) . H2O decomposes to stoichiometric UO2SeO3 . SeO2. This compound decomposes further to the same non-stoichiometric uranyl selenite-selenium dioxide phase as the ammonium compound.

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Documento generato il 25/10/20 alle ore 12:49:53