Fourier transform Raman spectroscopic study of Ba(SO4)x(CrO 4)1−x solid solution

✍ Scribed by J. M. Alía; H. G. M. Edwards; A. Fernández; M. Prieto

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 265 KB
• Volume: 30
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/(sici)1097-4555(199902)30:2<105::aid-jrs353>3.0.co;2-h

✦ Synopsis

solid solution (nature : hashemite) gel-grown crystals were studied using Fourier transform Ba(SO 4 ) x (CrO 4 ) 1-x Raman spectroscopy. The complex Raman spectrum of the end-member was studied in detail by means of BaCrO 4 bandshape analysis and component Ðtting procedures. Important e †ects of the crystalline Ðeld (both static and dynamic) were observed that could explain the evolution of the chromate anion Raman-active internal modes under the inÑuence of a second anion. SigniÐcant modiÐcations were likewise detected in the sulphate anion normal modes. The hindrance of the sulphate intermolecular couplings (dynamic e †ect of the crystalline Ðeld) when chromate anion replaces it in the unit cell could be the cause of the reported observations. It was possible to propose a qualitative assignment of the observed barium chromate Raman-active lattice modes by studying the evolution of such bands with the anion content. The six bands observed in the region 80-200 cm-1 of the barium chromate Raman spectrum can be interpreted as anion libration (one band), chromate anion translational vibrations (two bands) and barium-oxygen vibrations (three bands).