A detailed synchrotron X‐ray diffraction (XRD) study performed with a single crystal of BaVS₃ (barium vanadium trisulfide) in the temperature range between 10 and 295 K is reported. Aside from the known tetragonal–orthorhombic (240 K) and orthorhombic–monoclinic (69 K) phase transitions, in the 130 < T ≤ 295 K range the overall structure can be viewed as a host–guest (H–G) composite. The BaS₃ matrix is the host, while the V‐chains form the guest. The two subsystems lock in at T_LOCK = 130 ± 20 K. This temperature is marked by a symmetry change from orthorhombic to monoclinic. This results in the formation of twins, implying a structural phase transition identified here for the first time. From the refined structural data, it is possible to follow, starting already at 295 K downwards, the stepwise transformation of VS₆ octahedra into VS₅ tetragonal pyramids as the origin of the structure evolution. The new findings will yield a better understanding of the complex electronic phase diagram of BaVS₃.

中文翻译：

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BaVS3中的一维复合主客体结构

据报道，在10至295 K的温度范围内，用BaVS ₃（三硫化钡钒）单晶进行了详细的同步加速器X射线衍射（XRD）研究。除了已知的正方晶的斜方晶（240 K）和斜方晶单斜（69 K）相变，在130 < Ť ≤295 K范围的整体结构可以作为一个主客体（H-G）复合观看。BaS ₃矩阵是主机，而V链则构成来宾。两个子系统锁定在T _LOCK = 130±20K。此温度的特征是从斜方晶到单斜晶的对称变化。这导致孪晶的形成，这意味着在此首次识别出结构相变。从精炼的结构数据来看，可以从已经向下295 K开始，逐步将VS ₆八面体逐步转变为VS ₅四角锥，以此作为结构演化的起源。新发现将使人们更好地理解BaVS ₃的复杂电子相图。