Abstract Palygorskite is a clay mineral whose structure has not been successfully deciphered, even considering the simultaneous presence of the orthorhombic and monoclinic phases within the same sample. An interesting question, which has barely been considered until the moment to explain the difficulty of the resolution of its structure, is whether the fibrous morphology of palygorskite might enhance the presence of possibly oriented fibers which could influence some reflections in random powder diffraction experiments. To observe this influence of orientation, computer simulations considering a slight variation of the structural models proposed by Chisholm (1992) were performed. These simulations were added in different proportions to study the role that certain proportions of oriented fibers play in the resulting diffractograms. The most interesting changes are in the region of interest comprised between 4.5 and 4.0 A. Different contents in the two palygorskite phases with oriented components were also considered, affecting the resulting simulated diffractograms. The simulations were compared with experimental results, concluding that orientation can play a very important role in the diffractograms, therefore complicating even more the resolution of the structure of this mineral.

中文翻译：

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坡缕石粉末中定向纤维的存在及其对 X 射线衍射图的影响

摘要 坡缕石是一种粘土矿物，其结构尚未成功破译，即使在同一样品中同时存在斜方晶相和单斜晶相也是如此。一个有趣的问题，直到解释其结构分辨率的困难才被考虑，是坡缕石的纤维形态是否会增强可能定向纤维的存在，这可能会影响随机粉末衍射实验中的一些反射。为了观察取向的这种影响，考虑到 Chisholm (1992) 提出的结构模型的轻微变化，进行了计算机模拟。这些模拟以不同的比例添加，以研究特定比例的定向纤维在所得衍射图中所起的作用。最有趣的变化是在 4.5 到 4.0 A 之间的感兴趣区域。还考虑了具有取向成分的两个坡缕石相中的不同含量，影响了所得模拟衍射图。将模拟结果与实验结果进行了比较，得出的结论是取向在衍射图中起着非常重要的作用，因此使这种矿物结构的分辨率更加复杂。