Structural study of the apatite Nd8Sr2Si6O26 by laue neutron diffraction and single-crystal raman spectroscopy
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Date
2014-08-20
Journal Title
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Publisher
American Chemical Society
Abstract
A single-crystal structure determination of Nd8Sr2Si6O26 apatite, a prototype intermediate-temperature electrolyte for solid oxide fuel cells grown by the floating-zone method, was completed using the combination of Laue neutron diffraction and Raman spectroscopy. While neutron diffraction was in good agreement with P6₃/m symmetry, the possibility of P6₃ could not be convincingly excluded. This ambiguity was removed by the collection of orientation-dependent Raman spectra that could only be consistent with P6₃/m. The composition of Nd8Sr2Si6O26 was independently verified by powder X-ray diffraction in combination with electron probe microanalysis, with the latter confirming a homogeneous distribution of Sr and the absence of chemical zonation commonly observed in apatites. This comprehensive crystallochemical description of Nd8Sr2Si6O26 provides a baseline to quantify the efficacy of cation vacancies, oxygen superstoichiometry, and symmetry modification for promoting oxygen-ion mobility. © 2014 American Chemical Society
Description
Keywords
Electrolytes, Monocrystals, Fuel cells, Neutron diffraction, Raman spectroscopy, Oxygen ions
Citation
An, T., Orera, A., Baikie, T., Herrin, J. S., Piltz, R. O., Slater, P. R., & Sanjuán, M. L. (2014). Structural Study of the Apatite Nd8Sr2Si6O26 by Laue Neutron Diffraction and Single-Crystal Raman Spectroscopy. Inorganic Chemistry, 53(17), 9416-9423. doi: 10.1021/ic501558r