On the basis of thermal analysis (DSC, DTA, DTG), single crystal X-ray diffraction experiments, dielectric studies and optical observation, it is found that the (N₂H₅)₃[CdCl₅] crystal exhibits several structural phase transitions. At room temperature, the studied crystal exhibits ferroelastic properties and undergoes phase transition from the monoclinic to the orthorhombic phase on heating above 327 K. Upon subsequent cooling, two structural phase transitions at about 323 and 319 K are observed, where the crystal adopts orthorhombic symmetry. The presented phase transitions are unique due to the fact the first heating run results in different structural changes compared to those observed during cooling and subsequent heating/cooling runs. In the studied crystal, N₂H₅⁺ ions and 1D chains built up from {CdCl₅}³⁻ units bridged by Cl atoms occur. The phase transitions observed can be associated with reorientation of cations and partial disorder of cations as well as Cl atoms.

中文翻译：

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(N2H5)3[CdCl5] 晶体中的室温铁弹性和不寻常的相变序列

根据热分析（DSC、DTA、DTG）、单晶 X 射线衍射实验、介电研究和光学观察，发现 (N ₂ H ₅ ) ₃ [CdCl ₅] 晶体表现出几种结构相变。在室温下，所研究的晶体表现出铁弹性，并在加热至 327 K 以上时经历从单斜晶相到斜方晶相的相变。随后冷却后，观察到大约 323 和 319 K 处的两个结构相变，其中晶体采用正交对称. 所呈现的相变是独一无二的，因为与在冷却和随后的加热/冷却运行期间观察到的结构变化相比，第一次加热运行会导致不同的结构变化。在研究的晶体中，N ₂ H ₅ ⁺离子和一维链由 {CdCl ₅ } ^{3− 构成}由 Cl 原子桥接的单元出现。观察到的相变可能与阳离子的重新定向和阳离子以及 Cl 原子的部分无序有关。