Determination of crystal structure of omphacite

被引:0
作者
ZHANG Qifang MA Zhesheng and SHI Nicheng Centre of Remote Sensing Ministry of Metallurgical Industry Beijing China China University of Geosciences Beijing China [100029 ,100083 ]
机构
关键词
omphacite; crystal structure; Pn space group;
D O I
暂无
中图分类号
O76 [晶体结构];
学科分类号
0702 ; 070205 ; 0703 ; 080501 ;
摘要
<正> 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 s
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页码:944 / 949
页数:6
相关论文
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[1]  
Deer Howie,Zussman,Rock-forming minerals,Single-Chain Silicates,Vol.2A, 2nd ed. London: Longman . 1978