The crystal structure of stishovite under pressure up to 6 GPa
The crystal structure of stishovite under pressure up to 6 GPa
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高达 6 GPa 压力下的石英晶体结构
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
K. Koto
中科院分区：
文献类型：
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作者：
Masashi Sugiyama;S. Endo;K. Koto
在压力高达6.09GPa的条件下，用单晶X射线对硅镁石的晶体结构进行了分析。由晶格参数得到的线性压缩系数βa = 1.22×10−3，βc = 0.64×10−3 GPa−1，等温体积模量KT = 313 GPa。SiO_6八面体中的三种氧边中，共享边最短，压缩性最高，导致八面体的畸变随压力的增加而增强。SiO 6八面体的体积模量被评估为250 GPa，其小于四面体晶胞的体积模量。SiO 6八面体的共享边随压力的缩短可以解释为增加沿着c轴的阳离子-阳离子相互作用的屏蔽效应，并可能表明随压力的增加，stishovite的共价特征的增加趋势。
The crystal structure analyses of stishovite were carried out by X-rays using a single crystal under pressure up to 6.09 GPa. The linear compressibilities βa = 1.22×10−3 and βc = 0.64×10−3 GPa−1 and the isothermal bulk modulus of KT = 313 GPa were obtained from the lattice parameters. A shared-edge is the shortest of three kinds of oxygen edges in SiO6 octahedron and is of highest compressibility, resulting in an enhancement of distortion of the octahedron with increasing pressure. The bulk modulus of SiO6 octahedron is evaluated to be 250 GPa which is smaller than that of the tetragonal unit cell. Shortening of the shared-edge of SiO6 octahedron with pressure can be explained by shielding effect for increasing cation-cation interaction along the c-axis and may suggest an increasing tendency of covalent character of stishovite with pressure.