Parkin Sean, Cunningham Jeremy, Rawls Brian, Bender John E, Staples Richard J, Biros Shannon M
Department of Chemistry, University of Kentucky, Lexington, KY, 40506, USA.
Department of Chemistry, Grand Valley State University, Allendale, MI 49401, USA.
Acta Crystallogr E Crystallogr Commun. 2023 Mar 28;79(Pt 4):246-253. doi: 10.1107/S2056989023002700. eCollection 2023 Mar 1.
This paper compares variations on a structure model derived from an X-ray diffraction data set from a solid solution of chalcogenide derivatives of -1,2-bis-(di-phenyl-phosphan-yl)ethyl-ene, namely, 1,2-(ethene-1,2-di-yl)bis-(di-phenyl-phoshpine sulfide/selenide), CHPSSe. A sequence of processes are presented to ascertain the composition of the crystal, along with strategies for which aspects of the model to inspect to ensure a chemically and crystallographically realistic structure. Criteria include mis-matches between and , plots of | | | |, residual electron density, alerts, pitfalls of the OMIT command used to suppress ill-fitting data, comparative size of displacement ellipsoids, and critical inspection of inter-atomic distances. Since the structure is quite small, solves easily, and presents a number of readily expressible refinement concepts, we feel that it would make a straightforward and concise instructional piece for students learning how to determine if their model provides the best fit for the data and show students how to critically assess their structures.
本文比较了一种结构模型的多种变体，该模型源自-1,2-双（二苯基膦基）乙烯的硫族化物衍生物固溶体的X射线衍射数据集，即1,2-（乙烯-1,2-二基）双（二苯基膦硫化物/硒化物），CHPSSe。文中介绍了一系列确定晶体组成的过程，以及检查模型哪些方面以确保获得化学和晶体学上合理结构的策略。标准包括 和 之间的不匹配、| | | |的图、残余电子密度、 警报、用于抑制拟合不佳数据的OMIT命令的陷阱、位移椭球体的比较大小以及对原子间距离的严格检查。由于该结构相当小，易于解析，并且呈现出许多易于表达的精修概念，我们认为它将成为一篇直接且简洁的教学文章，供学习如何确定其模型是否最适合数据的学生使用，并向学生展示如何严格评估他们的结构。
