Structural and spectroscopic investigation of lanthanum-substituted strontium-oxybritholites

Journal of Chemical Sciences

K Bouzouita1²  E Ben Salem²  K Boughzala²  S Nasr²  F Kooli¹ 

[1] Department of Chemistry, Taibah University, P.O. Box 30002, Almadinah Almunawwarah, Saudi Arabia$$;U.R. Matériaux Inorganiques, Institut Préparatoire aux Etudes d’Ingénieurs, Rue Ibn, ElJazzr, 5019 Monastir, Tunisia$$

关键词: Strontium-oxybritholite;    Rietveld refinement;    Raman spectroscopy;    29Si MAS NMR spectroscopy.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

Lanthanum-substituted strontium-oxybritholites, Sr10-𝑥La𝑥(PO4)6-𝑥(SiO4)𝑥O with 𝑥 = 0, 2 and 4, prepared by solid state reaction were investigated by chemical analysis, powder X-ray diffraction, Raman and 29Si MAS NMR spectroscopies. The refinements of powder XRD patterns of the substituted compounds by the Rietveld method showed that the lanthanum occupied the two metal sites, i.e. (4f) and (6h) sites into the apatite structure, with a clear preference for the (6h) sites. A progressive shift of the free oxygen O(4) towards the centre of the triangles formed by the metal-atoms in the (6h) positions was observed when the lanthanum content increased. It led to the formation of a Sr/La(2)-O(4) strong bond, which might have increased the stability of these compounds. The bands of Raman spectra were assigned to the vibration modes of PO4 and SiO4 groups. The comparison of the results of 29Si MAS NMR analysis with those obtained with the 31P previously reported, suggested that both species occupied the same crystallographic sites.

【 授权许可】

Unknown