title: Further insights into the chemistry of the Bi-U-O system.
abstract: Cubic fluorite-type phases have been reported in the U(IV)O2-Bi2O3 system for the entire compositional range, but an unusual non-linear variation of the lattice parameter with uranium substitution has been observed. In the current extensive investigation of the uranium(iv) oxide-bismuth(iii) oxide system, this behaviour of the lattice parameter evolution with composition has been confirmed and its origin identified. Even under inert atmosphere at 800 °C, U(IV) oxidises to U(V)/U(VI) as a function of the substitution degree. Thus, using a combination of three methods (XRD, XANES and Raman) we have identified the formation of the BiU(V)O4 and Bi2U(VI)O6 compounds, within this series. Moreover, we present here the Rietveld refinement of BiU(V)O4 at room temperature and we report the thermal expansion of both BiU(V)O4 and Bi2U(VI)O6 compounds.
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Karin
authors.initials: K
authors.lastname: Popa
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Damien
authors.initials: D
authors.lastname: Prieur
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Dario
authors.initials: D
authors.lastname: Manara
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Naji
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Vigier
authors.affiliation: CEA, DEN, DEC/SESC, F-13108 Saint Paul Lez Durance Cedex, France.
authors.forename: Philippe M
authors.initials: PM
authors.lastname: Martin
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Oliver
authors.initials: O
authors.lastname: Dieste Blanco
authors.affiliation: Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, D-01314 Dresden, Germany.
authors.forename: Andreas C
authors.initials: AC
authors.lastname: Scheinost
authors.affiliation: Forschungszentrum Karlsruhe/K.I.T., Institute for Synchrotron Radiation - ANKA, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Prüβmann
authors.affiliation: Forschungszentrum Karlsruhe/K.I.T., Institute for Synchrotron Radiation - ANKA, Germany.
authors.forename: Tonya
authors.initials: T
authors.lastname: Vitova
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Philippe E
authors.initials: PE
authors.lastname: Raison
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Joseph
authors.initials: J
authors.lastname: Somers
authors.affiliation: European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, Germany. karin.popa@ec.europa.eu.
authors.forename: Rudy J M
authors.initials: RJ
authors.lastname: Konings