Solid solubility in the CeTi2O6–CeTiNbO6 system: a multi-element X-ray spectroscopic study

Abstract

In order to investigate the limits of solid solubility between Ce-brannerite (CeTi2O6) and Ce-aeschynite (CeTiNbO6), materials in the system CeTi2–xNbxO6 have been produced by a solid state route and characterised by XRD and XANES at the Ce L3-, Ti K- and Nb K-edges, including Rietveld method refinements and linear combination fitting. Significant solid solubility was observed at the brannerite end, with near-single-phase brannerite observed for x = 0.2, 0.4, and only minor aeschynite observed where x = 0.6 which was identified as exceeding the limit of solubility of Nb. All Nb was present as Nb5+, with the substitution of Nb5+ into the brannerite structure permitted by the reduction of the same fraction of Ce4+ to Ce3+. This work expands the crystal chemistry of the titanate brannerites, with Ce-site oxidation states of less than 4+ being possible where sufficient charge-balancing species are available on the Ti-site.

Metadata

Authors/Creators:

Dixon Wilkins, M.C. https://orcid.org/0000-0003-1520-7672
Stennett, M.C.
McCloy, J.S.
Corkhill, C.L. https://orcid.org/0000-0002-7488-3219

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