尼格里
- 网络NEGRIER
尼格里-
化学成分具SiO~2高和K2C>Na2O的特点，在尼格里四面体图解中，其成分点分布于火成岩与粘土沉积岩界线附近。富含重稀土元素Y和Yb。
Their chemical composition is characteristic of high SiO_2 content and K_2O > Na_2O , and in the Niggli 's tetrahedron classification diagram , their composition points concentrates near the boundary between igneous rock and clay sedimentary rock , and rich in heavy rare earth element Y and Yb .
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然后又介绍了与配位形相关的布拉菲胞选取准则及尼格里胞理论：紧接着引入配位形的概念；
And then selection rule of Bravais ' cell and Niggli 's cell theory are introduced in turn ; after that , conception of coordination shape is presented and discussed ;