Determination of crystal structure of omphacite
Determination of crystal structure of omphacite作者机构:Minist Met Ind Ctr Remote Sensing Beijing 100029 Peoples R China China Univ Geosci Beijing 100083 Peoples R China
出 版 物:《Chinese Science Bulletin》 (科学通报(英文版))
年 卷 期:1999年第44卷第10期
页 面:944-949页
核心收录:
学科分类:07[理学] 070205[理学-凝聚态物理] 08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程(可授工学、理学学位)] 0703[理学-化学] 0702[理学-物理学]
主 题:omphacite crystal structure Pn space group.
摘 要:The chemical formula of omphacite was expressed with (MⅡMⅠ)(Si, AI)2O6.Cations that occupied the MⅡ site were large cations such as Ca or Na, and Na/(Na+Ca) ratio ranged from 0.2 to 0.8; the 6-coordinated MⅠ site accommodated cations such as Mg, Fe2+,Al, Fe3+ ,and Al/(Al+Fe3+) ratio was more than 0.5 Omphacite space groups reported were C2/c, P2, P2/n, P2/c, cell parameters are a0 = 0.9600—0.9630 nm, b0 = 0.8750—0.8830 nm, C0 =0.5230—0.5290 nm,β = 106°40’—107°10’. The sample was picked up from the eclogites in Zhucheng County, Shangdong Province. The intensity data were collected with the RIGAKU RASA Ⅱ -S four-circle single crystal diffractometer. The correct structure model was obtained by using the Patterson method and Fourier synthesis, SHELX-76 program, structure refinement with 905 independent diffraction points (|F0| 3σ|F0 |). After the structure parameter refinement, the R-factor reduced to 0.0515. The crystal structure analysis indicates that omphacite has a new