采用无水氟化物直接熔化法得到了CdF2－BaF2－LiF系统玻璃的玻璃形成区，用X射线衍射和分子动力学计算机结构模拟等手段研究了成分为36CdF2－34BaF2－30LiF（mol％）的玻璃的结构．研究表明，Cd原子主要为6、7和8配位，Ba原子主要为8配位，Cd－F的平均键长为2.29A玻璃结构可以看作是由Li+连接的[CdFn]多面体共边或共角堆积而成．Cd－Cd键长在共边连接时为3.52A共角时为4.03A对氟化物玻璃中Li+原子所起的作用进行了比较．
Glass forming regions in the CdF2-BaF2-LiF system were determined through melting-quen-ching technique. The structure of 36CdF2-34BaF2-30LiF
(mol%) (CBL glass) was studied by X-ray diffraction and molecular dynamics simulation methods. The Cd atoms are six-, seven- and eightfold coordinated by fluorines.
The average Cd--F bond length is 2.29A. The Cd--Cd atom distance is about 3.52A for edge-sharing and 4.03A for corner-sharing in the MD-derived glass. The
glass structure can be discribed as a network made up of edge-sharing and corner-sharing [CdFn] polyhedra which are partial linked by
Li+ ions. The role of Li+ ions in the fluoride glasses was discussed. It was proposed that Li+ may play the outpolarization effort in fluoride glass as
it does in the oxide one. This effort can play a positive role to the connectivity of the network based on the good glass formers. However, in the
glass based on the weak-bonded glass formers, the relative strong Li--F bond results in a decrease of its chemical durability as it does in the CdF2-BaF2-LiF system.
参考文献
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| [2] | Poulain M. Nature, 1981, 293 (5830): 279--280 2 Iwamoto N, Umesaki N, Takahashi M, et al. J. Non-cryst. Solids, 1987, 95 & |
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