• 主题
高级搜索  >
历史搜索 清空历史
首页> 美国卫生研究院文献>Proceedings of the National Academy of Sciences of the United States of America >Arizona porphyry copper/hydrothermal deposits II: Crystal structure of ajoite (K + Na)3Cu20Al3Si29O76(OH)16⋅∼8H2O
【2h】

Arizona porphyry copper/hydrothermal deposits II: Crystal structure of ajoite (K + Na)3Cu20Al3Si29O76(OH)16⋅∼8H2O

机译：亚利桑那斑岩铜/水热矿床II：重晶石的晶体结构（K + Na）3Cu20Al3Si29O76（OH）16⋅〜8H2O

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务，本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文，但由于OA文献来源多样且变更频繁，仍可能出现获取不到、文献不完整或与标题不符等情况，如果获取不到我们将提供退款服务。请知悉。
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A crystal from the type locality Ajo, AZ, yielded just enough intensity from streaked diffractions using synchrotron x-rays at the Advanced Photon Source to solve the crystal structure with composition (K + Na)3Cu20Al3Si29O76(OH)16⋅∼8H2O; triclinic, P1̄, a = 13.634(5) Å, b = 13.687(7), c = 14.522(7), α = 110.83(1)°, β = 107.21(1), γ = 105.68(1); refined to a final R = 12.5%. Electron microprobe analysis yielded a similar chemical composition that is slightly different from the combined chemical and electron microprobe analyses in the literature. The ajoite structure can be described as a zeolitic octahedral-tetrahedral framework that combines the alternate stacking of edge-sharing octahedral CuO6 layers and curved aluminosilicate layers and strings. Channels bounded by elliptical 12-rings and circular 8-rings of tetrahedra contain (K and Na) ions and water. The Al atoms occupy some of the Si tetrahedral sites. Each Cu atom has near-planar bonds to four oxygen atoms plus two longer distances that generate a distorted octahedron. Valence bond estimates indicate that 8 oxygen atoms of 46 are hydroxyl. Only one alkali atom was located in distorted octahedral coordination, and electron microprobe analyses indicate K and Na as major substituents. The water from chemical analysis presumably occurs as disordered molecules of zeolitic type not giving electron density from diffraction. The high R factor results from structural disorder and many weak intensities close to detection level. The crystal chemistry is compared with shattuckite, Cu5(SiO3)4(OH)2, and planchéite, Cu8Si8O22(OH)4⋅H2O, both found in oxidized copper deposits of Arizona but only the former directly with ajoite.
机译：在先进光子源，使用同步加速器X射线，通过条纹衍射产生的强度刚好来自亚利桑那州阿霍类型的晶体，从而解决了组成为（K + Na）3Cu20Al3Si29O76（OH）16⋅〜8H2O的晶体结构；三斜线，P 1 ̄ ，a = 13.634（5）Å，b = 13.687 （7），c ＝ 14.522（7），α＝ 110.83（1）°，β＝ 107.21（1），γ＝ 105.68（1）；最终R = 12.5％。电子微探针分析产生的化学组成与文献中化学和电子微探针的组合分析略有不同。可将重晶石结构描述为一种沸石的八面体-四面体骨架，结合了边缘共享的八面体CuO6层和弯曲的硅铝酸盐层和细绳的交替堆叠。由四面体的椭圆形12环和圆形8环界定的通道包含（K和Na）离子和水。 Al原子占据了一些Si四面体位点。每个铜原子都具有与四个氧原子的近平面键以及两个更长的距离，从而产生扭曲的八面体。价键估计值表明46中的8个氧原子为羟基。只有一个碱金属原子处于扭曲的八面体配位状态，电子探针分析表明，K和Na为主要取代基。来自化学分析的水大概是作为沸石类型的无序分子而产生的，而没有从衍射中获得电子密度。高R因子由结构紊乱和许多接近检测水平的弱强度引起。将晶体化学与硅藻土Cu5（SiO3）4（OH）2和方铅矿Cu8Si8O22（OH）4⋅H 2 O进行了比较，二者均在亚利桑那州的氧化铜矿床中发现，但仅在前者中发现。直接与ajoite。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号