A comprehensive examination of the local- and long-range structure of Sb6O13 pyrochlore oxide

RODRIGUES, J.E.; FALCÓN, H.; MAYER, S.F.; FERNÁNDEZ-DÍAZ, M.T.; ALONSO, J.A.; MARINI, C.; ASENSIO, M.C.

Scientific Reports

Nature Research

Lugar: Londres; Año: 2020 vol. 10

The crystal structure of the Sb6O13 oxide, exhibiting a defect pyrochlore crystal structure with atomic vacancies, has been studied using a complete set of state-of-the-art techniques. The degree of antimony disproportionation in Sb3+ and Sb5+ valence states has been directly determined around 36% and 64%, respectively, using X-ray absorption near edge structure (XANES). These findings are in excellent agreement with our Rietveld analysis of synchrotron X-ray (SXRD) and neutron powder diffraction (NPD) results. Moreover, the highly distorted Sb3+ coordination due to its lone electron pair has been critically revisited. The bonding distances and coordination of Sb3+ and Sb5+ species closely agree with an extensive dynamic and crystallographic determination using the Extended X-ray Absorption Fine Structure (EXAFS) technique. Most importantly, the specific local disorder of the two distinctive Sb ions has been crosschecked monitoring their unusual Debye?Waller factors.