Three novel ionic co-crystals (ICCs) built from lithium perchlorate and β-alanine (LiClO₄·βAla, LiClO₄·2βAla-I, LiClO₄·2βAla-II) were obtained and structurally characterized. Crystals with a twofold excess of amino acid, LiClO₄·2βAla-I, were found to undergo a solvent-mediated phase transition, recrystallizing as the thermodynamically stable polymorph LiClO₄·2βAla-II. The transition was characterized by a series of PXRD measurements, observations performed under a microscope with polarized light and DSC experiments. Both polymorphs were found to exhibit virtually the same square-grid topology of lithium–alanine coordination sheets, yet they differ in symmetry and geometrical parameters of the networks. In the LiClO₄·βAla crystal structure, chain-like coordination polymers are formed. Responses to temperature change were determined for all three structures by performing a series of X-ray diffraction measurements in the 100–300 K range. Differences were elucidated with the help of a thermal tensor, which allowed us to identify the structural motifs most sensitive to temperature change.

中文翻译：

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LiClO4–β-丙氨酸离子共晶体的多态性和结构多样性

获得了三种由高氯酸锂和β-丙氨酸构建的新型离子共晶体（ICL）（LiClO ₄ ·βAla，LiClO ₄ ·2βAla-I，LiClO ₄ ·2βAla-II）并进行了结构表征。发现具有两倍过量氨基酸LiClO ₄ ·2βAla-I的晶体经历了溶剂介导的相变，重结晶为热力学稳定的多晶型LiClO ₄ ·2βAla-II。通过一系列PXRD测量，在具有偏光的显微镜下进行的观察以及DSC实验来表征转变。发现这两种多晶型物实际上表现出相同的锂-丙氨酸配位片方格拓扑，但是它们在网络的对称性和几何参数方面有所不同。在LiClO ₄ ·βAla晶体结构中，形成链状配位聚合物。通过在100–300 K范围内执行一系列X射线衍射测量，确定了所有三个结构对温度变化的响应。借助热张量阐明了差异，这使我们能够确定对温度变化最敏感的结构图案。