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Effect of Li 2 O Addition on the Preparation of (Y 2‐y Li y )Ti 2 O 7‐y
Author(s) -
Su WenPing,
Lee YuHsuen,
Hsieh ChingTien,
Sheu HwoShuenn,
Lee JyhFu,
Chiang YongPing,
Kao H.C. I.
Publication year - 2009
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200900161
Subject(s) - chemistry , valence (chemistry) , ionic radius , xanes , pyrochlore , ion , crystallography , analytical chemistry (journal) , solid solution , phase (matter) , spectral line , physics , organic chemistry , chromatography , astronomy
A new series of (Y 2‐y Li y )Ti 2 O 7‐y having an ordered pyrochlore phase was prepared by a solid state reaction method with a solid solution range of 0.05 ≥ y ≥ 0.10. Unit cell parameters obtained by the Rietveld refinement method shows that the a ‐axis decreases linearly with increasing the amount of Li ion addition, indicating the successful incorporation of the Li ion into unit cell. The average x‐fractional coordinate of the O(1) site depends on the ionic radius ratio of r(A 3 +)/r(Ti 4+ ) in the A 2 Ti 2 O 7 with a pyrochlore phase. The Ti K ‐edge XANES spectra of the (Y 2‐y Li y )Ti 2 O 7‐y show that the valence of the Ti ions is slightly less than 4 so that Ti is in the mixed valence state. Average particle size increases with increasing the amount of extra Li ion addition, which acts as a flux to lower the melting point of the materials.