The molecular and solid‐state structure of azulene both raise fundamental questions. Therefore, the disordered crystal structure of azulene was re‐refined with invariom non‐spherical atomic scattering factors from new single‐crystal X‐ray diffraction data with a resolution of d = 0.45 Å. An unconstrained refinement results in a molecular geometry with C_s symmetry. Refinements constrained to fulfill C_2v symmetry, as observed in the gas phase and in high‐level ab initio calculations, lead to similar figures of merit and residual densities as unconstrained ones. Such models are consistent with the structures from microwave spectroscopy and electron diffraction, albeit they are not the same. It is shown that for the disorder present in azulene, the invariom model describes valence electron density as successfully as it does for non‐disordered structures, although the disorder still leads to high correlations mainly between positional parameters. Lattice‐energy minimizations on a variety of ordered model structures using dispersion‐corrected DFT calculations reveal that the local deviations from the average structure are small. Despite the molecular dipole moment there is no significant molecular ordering in any spatial direction. A superposition of all ordered model structures leads to a calculated average structure, which explains not only the experimental determined atomic coordinates, but also the apparently unusual experimental anisotropic displacement parameters.

中文翻译：

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重访Azulene：经典结构实例的固态结构，不变模型和晶格能量最小化。

z烯的分子和固态结构都提出了基本问题。因此，根据新的单晶X射线衍射数据（分辨率为d = 0.45Å），用不变的非球形原子散射因子重新定义了无序氮青铜的晶体结构。不受限制的精修会导致分子几何形状具有C _s对称性。精炼必须满足C _{2 v}对称性，如在气相和高水平从头算中观察到的计算得出的品质因数和残留密度与无约束的相似。这些模型与微波光谱和电子衍射的结构一致，尽管它们并不相同。研究表明，对于a石中存在的无序性，不变性模型成功地描述了价电子密度，就像对无序结构所做的一样，尽管无序性仍主要导致位置参数之间的高度相关。使用色散校正DFT计算对各种有序模型结构进行的晶格能量最小化显示，与平均结构的局部偏差很小。尽管存在分子偶极矩，但在任何空间方向上都没有明显的分子有序。