晶体结构解析案例57(孪晶拆分)

DJ_Tokyo

相关软件或概念：APEX4[1] (Version 2021.4-1); Olex2[2] (Version: Olex2-1.5); PLATON[3] (Version: 60124); SHELXL[4] (Version: SHELXL-2019/3); SHELXT[5]; CCDC[6]

案例来源：CCDC2335257, DOI: 10.5517/ccdc.csd.cc2jd0wv.

该结构实际上按照正常步骤还原得到的数据凑合也可以用，如图1所示。

▲图1 正常处理结果

倒易空点阵点表明该晶体明显是孪晶，如图2所示。

▲图2 倒易空间点阵点

经孪晶拆分后，数据结果如图3所示，R因子明显得到改善。

▲图3 孪晶拆分结果

具体处理过程请参阅视频：

单晶结构解析练习22(孪晶拆分)：https://www.bilibili.com/video/BV1ym411f7qX

参考文献

[1]Bruker (2021). APEX4 (Version2021.4-1). Program for Data Collection onArea Detectors. Bruker AXS Inc., Madison, Wisconsin, USA.

[2]Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann,H. OLEX2: A complete structure solution,refinement and analysis program. J. Appl. Cryst. 2009, 42, 339–341.

[3] (a) Spek, A. L. Single-crystal structure validationwith the program PLATON. J. Appl.Cryst. 2003, 36, 7–13. (b) Spek,A. L. Structure validation in chemical crystallography. Acta Cryst. 2009, D65, 148–155. (c) Spek, A. L. What makes a crystal structure reportvalid? Inorg. Chim. Acta 2018, 470, 232–237. (d) Spek, A. L. checkCIFvalidation ALERTS: what they mean and how to respond. Acta Cryst. 2020, E76, 1–11.

[4](a) Sheldrick, G. M. SHELXL-2019/3, Program for Crystal Structure Refinement,University of Göttingen, Germany, 2019. (b) Sheldrick, G. M. A short history ofSHELX. Acta Cryst. 2008, A64, 112–122. (c) Sheldrick, G. M.Crystal structure refinement with SHELXL.Acta Cryst. 2015, C71, 3–8. (d)Lübben, J.; Wandtke, C. M.; Hübschle, C. B.; Ruf, M.; Sheldrick, G. M.;Dittrich, B. Aspherical scattering factors for SHELXL – model, implementation and application. Acta Cryst. 2019, A75, 50–62.

[5]Sheldrick, G. M. SHELXT – Integratedspace-group and crystal structure determination. Acta Cryst. 2015, A71, 3–8.

[6](a) Allen, F. H. The Cambridge Structural Database: a quarter of a millioncrystal structures and rising. ActaCryst. 2002, B58, 380–388. (b) Allen, F. H. TheCambridge Structural Database: a quarter of a million crystal structures andrising. Acta Cryst. 2016, B72, 171–179.

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