%0 Journal Article
%T Determination of crystal structure of omphacite
%A Qifang Zhang
%A Zhesheng Ma
%A Nicheng Shi
%J Chinese Science Bulletin
%@ 1861-9541
%D 1999
%I 
%R 10.1007/BF02885072
%X The chemical formula of omphacite was expressed with (MII MI) (Si, Al)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 area 0 = 0.9600每0.9630 nm,b{on0} = 0.8750每0.8830 nm,c0 = 0.5230每0.5290 nm,汕 = 106∼40∩每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| > 3考|F 0|). After the structure parameter refinement, the R-factor reduced to 0.0515. The crystal structure analysis indicates that omphacite has a new space group〞Pn space group.
%K omphacite
%K crystal structure
%K Pn space group
%U http://link.springer.com/article/10.1007/BF02885072