title: Refinement of the α-U4O9 crystalline structure: new insight into the U4O9 → U3O8 transformation.
abstract: The oxidation reaction of UO(2) into U(3)O(8) is studied as a function of the crystalline distortion of interstitial oxygen clusters, named cuboctahedra, which appear in U(4)O(9) and U(3)O(7) intermediate phases. For that purpose, the refinement of α-U(4)O(9) was performed because this phase undergoes a trigonal distortion from cubic β-U(4)O(9) when the temperature is decreased. In α-U(4)O(9), the cuboctahedra can be described as crumpled sheets taken from a fragment of U(3)O(8). The manner by which the accumulation of crumpled sheets can lead to the formation of U(3)O(8) is discussed.
authors.affiliation: CEA/DEN/DEC , Bat 352, Cadarache 13108, Saint Paul lez Durance, France. Lionel.desgranges@cea.fr
authors.forename: L
authors.initials: L
authors.lastname: Desgranges
authors.forename: G
authors.initials: G
authors.lastname: Baldinozzi
authors.forename: D
authors.initials: D
authors.lastname: Siméone
authors.forename: H E
authors.initials: HE
authors.lastname: Fischer