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Structure and bonding in cerium oxysulfide compounds. II—Comparative lattice dynamics calculations on Ce 2 O 2 S and Ce 2.0 O 2.5 S
Author(s) -
Sourisseau C.,
Fouassier M.,
Mauricot R.,
Boucher F.,
Evain M.
Publication year - 1997
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(199712)28:12<973::aid-jrs192>3.0.co;2-f
Subject(s) - cerium , raman spectroscopy , chemistry , crystal structure , lattice (music) , lattice energy , analytical chemistry (journal) , infrared , crystallography , inorganic chemistry , physics , optics , organic chemistry , acoustics
Using the previously reported vibrational results (infrared, Raman and resonance Raman spectra) for the Ce 2 O 2 S and Ce 2.0 O 2.5 S solid compounds (see Part I), comparative lattice dynamics calculations were performed. These calculations allow one to reproduce satisfactorily the experimental wavenumbers and to propose more confident vibrational assignments for the statistically disordered Ce 2.0 O 2.5 S, on the assumption of a D 3 symmetry crystal structure. In particular, it is shown that the cerium to oxygen bonding forces are distinct in the two oxysulfides: the f (Ce–O1) stretching force constants increase significantly from 90 N m ‐1 in the Ce 3+ ‐containing Ce 2 O 2 S phase to 110 and 140 N m ‐1 for the (Ce–O1) axial and equatorial forces, respectively, in the Ce 2.0 O 2.5 S oxidation product. The fact that the latter value (140 N m ‐1 ) compares well with that estimated in cerium dioxide CeO 2 supports previous conclusions from the optical study, i.e. that Ce 2.0 O 2.5 S is more likely described as a Ce 4+ ‐containing sample. © 1997 John Wiley & Sons, Ltd.