Simple Approach for Selective Crystal Growth of Intermetallic Clathrates
Simple Approach for Selective Crystal Growth of Intermetallic Clathrates
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金属间包合物选择性晶体生长的简单方法
DOI：
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发表时间：
2011
期刊：
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通讯作者：
G. Nolas
中科院分区：
文献类型：
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作者：
S. Stefanoski;M. Beekman;W. Wong;P. Zavalij;G. Nolas
本文报道了一种合成单晶金属间包合物的新方法。在封闭的体积内，在单轴压力下，气相与空间分离的石墨发生反应，碱金属从碱硅化物前驱体中缓慢析出，形成二元金属间笼形物Na8Si46和Na24Si136的单晶。本文首次报道了Na8Si46单晶结构的细化。在Na8Si46和Na24Si136多面体中，观察到所有的Si框架位点都被完全占据，而Na在两个多面体中都被完全占据。除了包含一种简单的方法来选择性地、相纯地生长包合物，如Na8Si46或Na24Si136，这是以前难以实现的，这种或类似的方法适用于从不同的碱金属前体制备新的组合物。
We report on a new method for the synthesis of single-crystal inter-metallic clathrates. Alkali-metal is slowly removed from an alkali-silicide precursor by reaction of the vapor phase with spatially separated graphite, in a closed volume under uniaxial pressure, to form single-crystals of the binary intermetallic clathrates Na8Si46 and Na24Si136. Single-crystal structure refinement for Na8Si46 is reported for the first time. For both Na8Si46 and Na24Si136, full occupation of all Si framework sites as well as full Na occupancy in both polyhedra was observed. In addition to comprising a simple method for selective, phase-pure crystal growth of clathrates such as Na8Si46 or Na24Si136 which was previously challenging to achieve, this or similar approaches are applicable in the preparation of new compositions from different alkali-metal precursors.