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众所周知,在高压条件下,硅酸盐矿物和玻璃中的硅可以形成八面体配位,但在通常的低压硅酸盐玻璃中,硅为四面体配位,因为玻璃中硅的八面体配位会迫使形成周期性结构,破坏玻璃的非晶态。目前几乎没有文献报道在低压硅酸盐玻璃中存在八面体配位的硅。很久以来,人们一直对于含磷的硅酸盐玻璃和熔体有很大兴趣,因为一方面含磷的硅酸盐玻璃是很有前景的光导纤维材料,另一方面,在地球化学上P_2O_5加入到岩浆体系中,会导致液相不混溶,降低岩浆的液相线温度和粘度,影响元素在固相-液相和液相-液相之间的分配,尽管有报道证明在钠的磷硅酸盐玻璃中存在八面体配位的硅,但此结果仍有一定的争议。本文采用同步辐射的硅K边X射线吸收光谱研究了硅在SiO_2-P_2O_5和Na_2O-SiO_2-P_2O_5体系的磷硅酸盐玻璃中的结构与配位,以及硅的配位几何随玻璃中P_2O_5含量的变化。
It is well known that under high pressure conditions, silicon in silicate minerals and glass can form octahedral coordination, but in typical low-pressure silicate glasses, silicon is tetrahedrally coordinated because the octahedral coordination of silicon in the glass Will force the formation of a cyclical structure, destroy the amorphous glass. At present, almost no literature reports octahedrally coordinated silicon in low-pressure silicate glass. People have long been interested in phosphorus-containing silicate glasses and melts because, on the one hand, phosphorus-containing silicate glass is a promising optical fiber material and, on the other hand, geochemically, P 2 O 5 is added To the magma system, it leads to immiscibility in the liquid phase, lowering the liquidus temperature and viscosity of the magma and affecting the distribution of the elements between the solid-liquid phase and the liquid-liquid phase, although it has been reported that phosphorus There is octahedral coordination silicon in silicate glass, but the result is still somewhat controversial. In this paper, the synchrotron radiation K-side X-ray absorption spectra of silicon in SiO_2-P_2O_5 and Na_2O-SiO_2-P_2O_5 system of phosphorus silicate glass structure and coordination, as well as the coordination geometry of silicon with glass P_2O_5 content The change.