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Fe and Cr K‐edges EXAFS Study of Double Perovskite (Sr 2 ‐ x Ca x )FeMoO 6 (0 ≤ x ≤ 2.0) and Sr 2 CrMO 6 (M = Mo, W) Systems
Author(s) -
Chan T. S.,
Liu R.S.,
Jang L.Y.
Publication year - 2005
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.200500101
Subject(s) - ionic radius , chemistry , extended x ray absorption fine structure , monoclinic crystal system , bond length , tetragonal crystal system , crystallography , ionic bonding , perovskite (structure) , crystal structure , spectroscopy , analytical chemistry (journal) , absorption spectroscopy , ion , physics , organic chemistry , chromatography , quantum mechanics
The local structure of the double perovskite (Sr 2‐x Ca x )FeMoO 6 (0 ≤ × ≤ 2.0) and Sr 2 CrMO 6 (M = Mo, W) systems have been probed by extended X‐ray absorption fine structure (EXAFS) spectroscopy at the Fe and Cr K ‐edges. We found Fe‐O (ave) distance apparently decreases from 1.999 Å (x = 0) to 1.991 Å (x = 1.0) in (Sr 2‐x Ca x )FeMoO 6 (tetragonal structure). When x is increased further from 1.5 to 2.0, the Fe‐O bond distance decreased from 2.034 Å to 2.012 Å (monoclinic structure). In addition, Cr‐O, Sr‐Cr, and Cr‐Mo bond distances in Sr 2 CrWO 6 are all slightly larger than the bond distances of Sr 2 CrMoO 6 , which is due to the ionic radius of the W 5+ (0.62 Å) which is larger than the ionic radius of Mo 5+ (0.61 Å). The results are consistent with our XRD refinements data.