高压相变晶体化学:Ⅰ.高压下SiO_2物相氧硅离子的半径变化和迁移行为  

High-Pressure Phase Transition Crystal Chemistry: Ⅰ. Changes of Ionic Radius and Migration Behave in SiO_2 Phases Under High Pressure

作　　者：施倪承[1] 李国武[1] 马喆生[1] 熊明[1] 

机构地区：[1]中国地质大学(北京)X射线衍射实验室,北京100083

出　　处：《矿物学报》2010年第3期355-360,共6页Acta Mineralogica Sinica

基　　金：国家自然科学基金项目(批准号:40872043)

摘　　要：高压下随着压力增加,氧化物及硅酸盐矿物中的阳离子会发生从配位数低的多面体向配位数高的多面体迁移的现象,这种迁移是由于阴阳离子半径的比值发生改变引起的。对SiO2在高压下形成的各种多形的氧和硅的离子半径进行计算,发现氧离子半径是随压力增加及相变的发生而逐渐缩小,但硅离子半径随压力增加及相变的发生而有明显的增大。这种现象可能是在高压下离子化合物逐渐向金属相化合物转变引起的。Under the condition of high pressure,the cations of silicon in oxide or silicate minerals can occur migration phenomenon from low coordination number polyhedra to high coordination number polyhedra with increasing pressure.This migration is due to the change with radius ratio of cations to anions.Under high pressure the ionic radii of oxygen and silicon have been calculated for different SiO2 polymorphs.It is indicated that the ionic radius of oxygen decreases gradually with increasing pressure,but the cation radius of silicon increases with increasing pressure and the occurrence of phase transitions.This phenomenon may be due to the transitions from ionic compounds to metallic phases under high pressures.

关 键 词：SiO2多形 高压相变晶体化学 配位多面体 离子半径 

分 类 号：O722[理学—晶体学] P575.5[天文地球—矿物学]