Structural characteristics of solid and liquid crystalline phases of 7OS5 (4‐n‐pentylphenyl‐4′‐n‐heptyloxythiobenzoate), the achiral smectogenic mesogen with the shortest terminal carbon chain in the nOS5 homologous series, are studied by complementary methods. Simultaneously perfomed X‐ray diffraction and differential scanning calorimetry occur to be a powerful tool to study metastable phases. The single crystal structure of a high‐temperature phase, supercooled from the room temperature down to −183°C [orthorhombic crystal system; space group Pca2₁; a = 54.285 (5) Å, b = 5.5843 (3) Å, c = 14.841 (1) Å, Z = 8] is determined. Lamellar ordering of elongated molecules is stabilized by hydrogen bonds . Temperature dependence of unit‐cell parameters in two crystal phases as well as structural parameters of liquid crystalline phases (smectic layer spacing, tilt angle, average distance between the long axes of molecules and correlation lengths) are determined by X‐ray diffraction. The obtained results are compared with the data available for other compounds in the nOS5 homologous series.

中文翻译：

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构影化合物7OS5的单晶X射线结构测定和温度依赖性结构研究

7OS5的固体和液体结晶相（4-结构特性Ñ -pentylphenyl -4'- Ñ -heptyloxythiobenzoate），非手性介晶smectogenic与在最短的末端碳链Ñ OS5同源系列，通过互补的方法的研究。同时进行的X射线衍射和差示扫描量热法是研究亚稳态相的有力工具。高温相的单晶结构，从室温过冷至-183°C [斜方晶系；空间群Pca 2 ₁ ; a = 54.285（5）Å，b = 5.5843（3）Å，c = 14.841（1）Å，Z = 8]。细长分子的层状有序性通过氢键得以稳定。通过X射线衍射确定两个晶相中晶胞参数的温度依赖性以及液晶相的结构参数（近晶层间距，倾斜角，分子长轴之间的平均距离和相关长度）。将获得的结果与n OS5同源系列中其他化合物的可用数据进行比较。