Synthesis and characterization of uranium (IV) phosphate-hydrogenphosphate hydrate and cerium (IV) phosphate-hydrogenphosphate hydrate
- Groupe de Radiochimie, Institut de Physique Nucleaire d'Orsay, Universite Paris-Sud-11, Bat. 100, 91406 Orsay (France)
A new uranium (IV) phosphate of proposed formula U{sub 2}(PO{sub 4}){sub 2}HPO{sub 4}.H{sub 2}O, i.e. uranium phosphate-hydrogenphosphate hydrate (UPHPH), was synthesized in autoclave and/or in polytetrafluoroethylene closed containers at 150{sup o}C by three ways: from uranium (IV) hydrochloric solution and phosphoric acid, from uranium dioxide and phosphoric acid and by transformation of the uranium hydrogenphosphate hydrate U(HPO{sub 4}){sub 2}.nH{sub 2}O. The new product appears similar to the previously published thorium phosphate-hydrogenphosphate hydrate Th{sub 2}(PO{sub 4}){sub 2}HPO{sub 4}.H{sub 2}O (TPHPH). From preliminary studies, it was found that UPHPH crystallizes in monoclinic system (a=2.1148(7)nm, b=0.6611(2)nm, c=0.6990(3)nm, {beta}=91.67(3){sup o} and V=0.9768(10)nm{sup 3}). Heated under inert atmosphere, this compound is decomposed above 400{sup o}C into uranium phosphate-triphosphate U{sub 2}(PO{sub 4})P{sub 3}O{sub 10}, uranium diphosphate {alpha}-UP{sub 2}O{sub 7} and diuranium oxide phosphate U{sub 2}O(PO{sub 4}){sub 2}. Crystallized cerium (IV) phosphate-hydrogenphosphate hydrate Ce{sub 2}(PO{sub 4}){sub 2}HPO{sub 4}.H{sub 2}O (CePHPH) was also synthesized from (NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 6} and phosphoric acid solutions by the same method (monoclinic system: a=2.1045(5)nm, b=0.6561(2)nm, c=0.6949(2)nm, {beta}=91.98(1){sup o} and V=0.9588(9)nm{sup 3}). When heating above 600{sup o}C, cerium (IV) is reduced into Ce (III) and forms a mixture of CePO{sub 4} (monazite structure) and CeP{sub 3}O{sub 9}.
- OSTI ID:
- 20725873
- Journal Information:
- Journal of Solid State Chemistry, Vol. 178, Issue 4; Other Information: DOI: 10.1016/j.jssc.2005.01.005; PII: S0022-4596(05)00009-5; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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