Xhyphen;ray diffraction study of Na+ions coordination in sodium borate glasses

摘要

Xhyphen;ray diffraction measurements were performed on glasses of the type Na2Ondash;B2O3and Li2Ondash;B2O3, in which the maximum content of Me2O is 0.3 mol per 1 mol of B2O3. By subtracting the radial distribution functions of the Li2Ondash;B2O3samples from those of Na2Ondash;B2O3glasses having the same molar ratios, difference curves were obtained in which peaks coming from the distribution of nearest neighbor atoms around Na+ions were observed. The quantitative analysis showed that the environment of Na+ions is not a regular polyhedron. About 5.0ndash;5.5 O atoms surround Na+ions; on the average 3.4ndash;3.6 O atoms are 2.40ndash;2.44 Aring; distant from Na+ions while 1.5ndash;2.0 other O atoms are at a distance of 2.75ndash;2.80 Aring;.