کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10564459 | 970757 | 2005 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Infrared study of the vibrational behavior of SO42â guest ions matrix-isolated in metal (II) chromates (Me = Ca, Sr, Ba)
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
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چکیده انگلیسی
Infrared spectra of matrix-isolated SO42â guest ions in host chromate matrices - CaCrO4·2H2O, SrCrO4 and BaCrO4 are reported and discussed with respect to the SO stretching and OSO bending modes. When the larger CrO42â ions are replaced by the smaller SO42â ions the mean frequencies of the asymmetric stretching and bending modes (ν¯3 and ν¯4) as well as the frequencies of ν1 of the SO42â guest ions are shifted to lower wavenumbers as compared to those in the respective neat sulfates due to the smaller compression that the guest ions undergo at the host lattice sites (larger values of the unit-cell volumes of the neat chromates than those of the neat sulfates). The SO42â guest ions exhibit three bands corresponding to the ν3 modes as deduced from the site group analysis (C1 site symmetry in CaCrO4·2H2O and SrCrO4 and Cs site symmetry in BaCrO4). However, in the bending mode region the SO42â guest ions matrix-isolated in BaCrO4 and SrCrO4 display a higher local symmetry than the crystallographic one (probably D2d). An adequate measure for the SO42â guest ion distortion is the site group splitting Îνas and Îνmax (the difference between the highest and the lowest wavenumbered components of the SO stretching modes). The distortion of the SO42â guest ions in CaCrO4·2H2O is stronger than that in SrCrO4 and BaCrO4 due probably to the smaller ionic radius of the Ca2+ ions than those of the Sr2+ and Ba2+ ions, i.e. to the shorter CaO bond distances than the respective SrO and BaO bond distances.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Vibrational Spectroscopy - Volume 39, Issue 1, 15 September 2005, Pages 46-49
Journal: Vibrational Spectroscopy - Volume 39, Issue 1, 15 September 2005, Pages 46-49
نویسندگان
D. Stoilova, M. Georgiev, D. Marinova,