二氧化锗同类异构体在标化及高量锗测定中的影响

EFFECT OF DIFFERENT CRYSTALLINE STRUCTURES OF GeO_2 ON THE STANDARDIZATION AND DETERMINATION OF HIGH CONTENTS OF GERMANIUM

研究了用X 射线衍射分析纯二氧化锗分子结构与组成,以及结构中存在同类异构体时,不同分解方法对标定和锗测定结果的影响。提出了在锗滴定法中使用的基准二氧化锗,用Na2O2高温熔融分解,以消除因低温碱溶不完全,在标定时产生的误差导致锗结果偏高。拟定方法经实际运用,结果准确、满意。

Through a Xray diffraction study of samples of highpurity germanium dioxide obtained from different producers, its was found that the crystalline structures are different in some of the samples. For example, in one of the samples, the crystalline structure was found to be of hexagonal system, however, in another sample, besides the hexagonal system, some tetragonal crystalline structure was also found. The GeO2 of tetragonal system can only be dissolved by alkali fusion at high temperature and it is insoluble in the ordinary alkaline dissolution at low temperature, thus leading to the arising of error in both the stardardization and determination of high contents of germanium. It is proposed that to overcome this phenomenon, fusion with Na2O2 for the pure GeO2 is necessary, in titrimetric determinations.