One-dimensional infinite chain structures of [Al2(OH)4(H2O)4]X2 (X = I, Br, Cl): an aggregate of Al2 species and a precursor of Al(OH)3.
One-dimensional infinite chain structures of [Al2(OH)4(H2O)4]X2 (X = I, Br, Cl): an aggregate of Al2 species and a precursor of Al(OH)3.
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DOI：
10.1039/c3dt50811k
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发表时间：
2013-08
影响因子：
4
通讯作者：
Zhong Sun;Hui Wang;Ying Zhang;Jingshuang Li;Yangchen Zhao;Wuning Jiang;Li Wang
中科院分区：
文献类型：
--
作者：
Zhong Sun;Hui Wang;Ying Zhang;Jingshuang Li;Yangchen Zhao;Wuning Jiang;Li Wang
采用基于粉末X射线衍射数据的Rietveld全轮廓拟合技术，结合单晶结构求解和精细化方法，在[Al 2（OH）4（H2O）4]X2（X = I，Br，Cl）的结构中观察到一维无限锯齿状链状结构.这些结晶在相同的单斜晶系和相同的C2/c空间群与不同的晶胞参数从自发水解的解决方案的AlX 3。每个链由大量的AlO 6八面体组成，这些八面体分为两组，具有相反的取向，并通过边缘共享彼此连接。此外，抗衡离子散布在链之间，形成强的货车范德华相互作用。研究还发现，每个链是由Al 2物种（Al 2（OH）2（H2O）8（4+），由两个八面体Al（H2O）6（3+）单体共享一个边缘形成的二聚体）进一步水解形成的聚集体和用于构建无限六聚体环片层的构建单元。这是聚合铝化合物的三种新结构，很少从粉末XRD数据中得到解决，它们提供了Al 2物种聚集过程及其随后演变为无限锯齿形链以及进一步演变为无限的直接证据。六聚环层，如在诺水铝石和三水铝石中发现的。此外，它们也代表了前三个例子，其中每个聚合铝物种具有一维无限链结构形成的AlO 6八面体通过边缘共享只。
By a combination of the Rietveld full-profile fitting technique based on powder X-ray diffraction data and the single-crystal structure solving and refining method, one-dimensional infinite zigzag chain structures were observed in the structures of [Al2(OH)4(H2O)4]X2 (X = I, Br, Cl). These crystallize in the same monoclinic system and the same C2/c space group with different unit cell parameters from spontaneously hydrolyzed solutions of AlX3. Each chain is composed of a significant number of AlO6 octahedra that fall into two groups with reverse orientations and connect to each other by edge-sharing. Furthermore, the counterions intersperse among the chains forming strong van der Waals interactions. It was also discovered that each chain was an aggregate formed from the further hydrolysis of the Al2 species (Al2(OH)2(H2O)8(4+), a dimer formed by two octahedral Al(H2O)6(3+) monomers sharing an edge) and a building unit for constructing the infinite hexameric ring sheet in nordstrandite and gibbsite. These are three new structures, rarely solved from powder XRD data, of polyaluminum compounds, and they provide the first direct evidence of the aggregation processes of Al2 species and their subsequent evolution into an infinite zigzag chain as well as further evolution into an infinite hexameric ring layer as found in nordstrandite and gibbsite. Furthermore, they also represent the first three examples in which each polyaluminum species possesses a one-dimensional infinite chain structure formed by AlO6 octahedra via edge-sharing only.