Analytical Sciences

Characterization of Sb-doped Bi₂UO₆ Solid Solutions by X-ray Diffraction and X-ray Absorption Spectroscopy

N. L. MISRA,*1 A. K. YADAV,*2 Sangita DHARA,*1 S. K. MISHRA,*3 Rohan PHATAK,*1 A. K. POSWAL,*2 S. N. JHA,*2 A. K. SINHA,*4 and D. BHATTACHARYYA*2

*1 Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400094, India
*2 Applied Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai-400094, India
*3 Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400094, India
*4 Indus Synchrotron Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore-452013, India

The preparation and characterization of Sb-doped Bi₂UO₆ solid solutions, in a limited composition range, is reported for the first time. The solid solutions were prepared by solid-state reactions of Bi₂O₃, Sb₂O₃ and U₃O₈ in the required stoichiometry. The reaction products were characterized by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements at the Bi and U L₃ edges. The XRD patterns indicate the precipitation of additional phases in the samples when Sb doping exceeds 4 at%. The chemical shifts of the Bi absorption edges in the samples, determined from the XANES spectra, show a systematic variation only up to 4 at% of Sb doping and support the results of XRD measurements. These observations are further supported by the local structure parameters obtained by analysis of the EXAFS spectra. The local structure of U is found to remain unchanged upon Sb doping indicating that Sb⁺³ ions replace Bi⁺³ during the doping of Bi₂UO₆ by Sb.

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