TITLE:
More Insight on Structure of New Binary Cerium Borate Glasses
AUTHORS:
Gomaa El-Damrawi, Fawzeya Gharghar, Rawya Ramadan
KEYWORDS:
Borate, Cerium, Former Units, NMR Analysis
JOURNAL NAME:
New Journal of Glass and Ceramics,
Vol.8 No.1,
January
29,
2018
ABSTRACT: The structure of glasses in the system of xCeO2(100-x)B2O3, x = 30, 40, 50 mol% CeO2 has been explored for the first time by correlation between data obtained from XRD, FTIR and 11B NMR analyses. NMR spectroscopy andFTIR spectroscopy have confirmed that transformation rate of BO3 to BO4 groups is reduced by CeO2 addition.The concentration of Ce4-O-Ce4 is increased at the expense of both B4-O-Ce4 and B3-O-B4 linkages. Boron atoms are mainly coordinated with Ce4 sites as second neighbors due to increasing CeO4 species with further increase of CeO2 concentration. Increasing B4 fraction is considered due to forming of CeO4 with rate higher than that of BO4 units. The change of chemical shift of 11B nuclei upon exchanging B2O3 with CeO2 confirms that the central boron atoms would be coordinated with tetrahedral cerium atoms as second neighbors. The X-ray diffraction of cerium rich glass is clearly indicated that the formation of crystalline phases refers to CeO4, CeBO3and Ce(BO2)3 species.