The chemical formula of omphacite was expressed with （M<sub>Ⅱ</sub>M<sub>Ⅰ</sub>）（Si, AI）<sub>2</sub>O<sub>6</sub>.Cations that occupied the M<sub>Ⅱ</sub...The chemical formula of omphacite was expressed with （M<sub>Ⅱ</sub>M<sub>Ⅰ</sub>）（Si, AI）<sub>2</sub>O<sub>6</sub>.Cations that occupied the M<sub>Ⅱ</sub> site were large cations such as Ca or Na, and Na/（Na+Ca） ratio ranged from 0.2 to 0.8; the 6-coordinated M<sub>Ⅰ</sub> site accommodated cations such as Mg, Fe<sup>2+</sup>,Al, Fe<sup>3+</sup> ,and Al/（Al+Fe<sup>3</sup>+） ratio was more than 0.5 Omphacite space groups reported were C2/c, P2, P2/n, P2/c, cell parameters are a<sub>0</sub> = 0.9600—0.9630 nm, b<sub>0</sub> = 0.8750—0.8830 nm, C<sub>0</sub> =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 （|F<sub>0</sub>|】 3σ|F<sub>0</sub> |）. After the structure parameter refinement, the R-factor reduced to 0.0515. The crystal structure analysis indicates that omphacite has a new展开更多
文摘The chemical formula of omphacite was expressed with （M<sub>Ⅱ</sub>M<sub>Ⅰ</sub>）（Si, AI）<sub>2</sub>O<sub>6</sub>.Cations that occupied the M<sub>Ⅱ</sub> site were large cations such as Ca or Na, and Na/（Na+Ca） ratio ranged from 0.2 to 0.8; the 6-coordinated M<sub>Ⅰ</sub> site accommodated cations such as Mg, Fe<sup>2+</sup>,Al, Fe<sup>3+</sup> ,and Al/（Al+Fe<sup>3</sup>+） ratio was more than 0.5 Omphacite space groups reported were C2/c, P2, P2/n, P2/c, cell parameters are a<sub>0</sub> = 0.9600—0.9630 nm, b<sub>0</sub> = 0.8750—0.8830 nm, C<sub>0</sub> =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 （|F<sub>0</sub>|】 3σ|F<sub>0</sub> |）. After the structure parameter refinement, the R-factor reduced to 0.0515. The crystal structure analysis indicates that omphacite has a new
