A model for trace-element distribution in silicate structures
A model for trace-element distribution in silicate structures
复制标题
硅酸盐结构中微量元素分布的模型
DOI：
10.1180/minmag.1976.040.314.02
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发表时间：
1976
影响因子：
2.7
通讯作者：
M. Volfinger
中科院分区：
文献类型：
--
作者：
J. Iiyama;M. Volfinger
本文提出了一个扩展的固溶体局部晶格变形模型（J. T。Iiyama，1974 b）。先前已经假设固定在晶体中的外来原子引起局部晶格变形，这防止另一个外来原子占据变形区。由此产生的熵的固溶体从这个模型可以解释的特殊行为的离子交换反应观察到的碱金属和碱土金属元素在菱镁矿和白云母。目前的版本假设变形区不禁止外来原子，但在该区域可接受的外来原子的数量取决于已经固定在晶体中的外来原子的总数。该模型被成功地应用于解释离子交换等温线观察到的铯，钠，锂云母和允许估计的表观反应常数的离子交换。否则这是不可能的，因为即使在固定到晶体中的外来元素的IOppm范围内，交换等温线中也缺乏理想的稀溶液行为。结果表明，该模型可以解释Li在透长石中的特殊行为。
Summary This paper presents an extended version of the local lattice deformation model of solid solutions (J. T. Iiyama, 1974b). It has been assumed previously that a foreign atom fixed in a crystal causes local lattice deformation, which prevents another foreign atom from occupying the deformed zone. The resulting entropy of the solid solution from this model can explain the particular behaviour of ion-exchange reactions observed with alkali and alkali-earth elements in feldspars and in muscovite. The present version assumes that the deformed zone does not prohibit foreign atoms, but that the number of foreign atoms acceptable in this region depends on the total numbers of foreign atoms already fixed in the crystal. The model is applied successfully to explain ion-exchange isotherms observed with Cs, Na, and Li in micas and permits an estimation of the apparent reaction constant of the ion exchange. This is otherwise impossible because of the lack of ideal dilute-solution behaviour in exchange isotherms even at the IO ppm range of the foreign element fixed into the crystal. It is demonstrated that the model can explain the particular behaviour of Li in sanidine.