方钠石的原位高压X射线研究

The in-situ high-pressure X-ray diffraction of natural sodalite

在室温下使用金刚石对顶砧(DAC)高压装置和同步辐射光源,对架状硅酸盐矿物方钠石进行了原位高压X射线衍射实验,最高压力达到17.4GPa。在研究的压力范围内观察到在3GPa左右方钠石发生了一次相变,且压力大于6.3GPa时,d222出现异常增大。对方钠石在高压下相变以及d222增大的原因进行了分析,认为方钠石结构中存在着充填大阳离子的多面体笼和孔道,高压下这些笼和孔道容易扭曲变形,从而造成结构的改变。

In situ high-pressure energy dispersive X-ray diffraction （EDXI）） experiments on framework silicate sodalite were carried out by using the diamond anvil cell （DAC） device with a synchrotron radiation source at Beijing Synchrotron Radiation Facility （BSRF）. The maximal pressure recorded at room temperature in these experiments reached as high as 17.4 GPa. It was observed in this pressure range that sodalite underwent a phase transition at about 3 GPa and that the d222 value showed an abnormal increase when the pressure was higher than 6.3 GPa. The experimental results are explained on the basis of the pressure effects upon the cage and tunnel structures in sodalite.