Bi David Wenhua, Baral Priya Ranjan, Magrez Arnaud
Crystal Growth Facility, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), Switzerland.
Acta Crystallogr E Crystallogr Commun. 2021 May 14;77(Pt 6):634-637. doi: 10.1107/S2056989021004990. eCollection 2021 Jun 1.
The crystal structure of Ba(IO), penta-barium bis-(orthoperiodate), has been re-investigated at room temperature based on single-crystal X-ray diffraction data. In comparison with a previous crystal structure determination by the Rietveld method, an improved precision of the structural parameters was achieved. Additionally, low-temperature measurements allowed the crystal structure evolution to be studied down to 80 K. No evidence of structural transition was found even at the lowest temperature. Upon cooling, the lattice contraction is more pronounced along the axis. This contraction is found to be inhomogeneous along different crystallographic axes. The inter-atomic distances between different Ba atoms reduce drastically with lowering temperature, resulting in a closer packing around the IO octa-hedra, which remain largely unaffected.
基于单晶X射线衍射数据，在室温下对五钡双（原高碘酸盐）Ba(IO)₅的晶体结构进行了重新研究。与之前通过里特韦尔德方法测定的晶体结构相比，结构参数的精度得到了提高。此外，低温测量使得能够研究晶体结构在低至80 K时的演变。即使在最低温度下也未发现结构转变的证据。冷却时，晶格沿 轴的收缩更为明显。发现这种收缩在不同晶轴上是不均匀的。不同Ba原子之间的原子间距随着温度降低而急剧减小，导致围绕IO八面体的堆积更紧密，而IO八面体基本未受影响。
