Superionic behaviour in copper (I) iodide at elevated pressures and temperatures
Superionic behaviour in copper (I) iodide at elevated pressures and temperatures
复制标题
碘化亚铜 (I) 在高压和高温下的超离子行为
DOI：
10.1088/0953-8984/10/48/015
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
N. Gardner
中科院分区：
文献类型：
--
作者：
S. Hull;D. Keen;W. Hayes;N. Gardner
利用中子粉末衍射技术研究了碘化铜（I）在高温高压下的结构性质，探讨了压力对该化合物超离子性质的影响。在p = 1.30（8）GPa的压力下，随着温度的升高，观察到三种结构相变。第一种是在T = 444（6）K时从室温锌钛矿结构的CuI-III相转变为菱方结构的CuI-IV相。在CuI-IV中只有有限的阳离子无序，其随温度的升高而逐渐增加。间隙阳离子的优选位置是在稍微扭曲的面心立方（f.c.c.）阴离子亚晶格随后向无序f.c.c.结构相CuI-I在T = 694（5）K时出现。该相在所有测量的压力和温度下均显示出完全的阳离子无序。最后，CuI在T = 920（15）K发生进一步的相变。首次对这一高压相（标记为CuI-VII）进行了衍射研究，结果表明这一高压相是一个体心立方（b.c.c.）具有完全无序的阳离子子晶格的超离子。的阳离子被发现优先占据的四面体网站，以类似的方式在同构（环境压力）的超离子相，如和。简要介绍了超离子二元卤化物的结构系统学及其热致无序。
The structural properties of copper (I) iodide have been investigated at elevated pressures and temperatures using the neutron powder diffraction technique, to probe the effects of pressure on the superionic properties of this compound. On increasing temperature at a pressure of p = 1.30(8) GPa, three structural phase transitions are observed. The first is from the ambient temperature zincblende structured phase CuI-III to rhombohedral CuI-IV at T = 444(6) K. There is only limited cation disorder in CuI-IV which increases gradually with temperature. The preferred locations of the interstitial cations are sites between the tetrahedral and octahedral interstices within the slightly distorted face-centred cubic (f.c.c.) anion sublattice. A subsequent transition to the disordered f.c.c. structured phase CuI-I occurs at T = 694(5) K. This phase shows complete cation disorder at all measured pressures and temperatures. Finally, CuI undergoes a further phase transition at a temperature of T = 920(15) K. The first diffraction studies of this high pressure phase (labelled CuI-VII) are presented, which indicate that this phase is a body-centred cubic (b.c.c.) superionic with complete disorder of the cation sublattice. The cations are found to preferentially occupy the tetrahedral sites, in a manner similar to that in isostructural (ambient pressure) superionic phases such as and . The structural systematics of the superionic binary halide compounds and their thermally induced disorder are briefly summarized.