无序示例-碘二重无序2

DJ_Tokyo

相关软件或概念：Olex2[1] (Version: Olex2-1.5); SHELXL[2] (Version: SHELXL-2019/3); PLATON[3] (Version: 60124)

案例来源：CCDC2339540, DOI: 10.5517/ccdc.csd.cc2jjh1m; CCDC 2340266, DOI:10.5517/ccdc.csd.cc2jk7gt.

该结构中三个碘原子附近均有残余峰，MaxPeak = 1.8，Min Peak= -1.9，如图1所示。

▲图1 碘附近残余电子密度峰

虽然该残余峰并未触发AB级警报，但鉴于该处残余电子峰，可考虑对其做二组分无序处理，无序处理后结果如图2所示。

▲图2 碘二重无序处理结果

无序处理前后各项指标参数比变化对比如下，可以看出，无序处理后，各项指标参数均得到较大改善。

	Max  Peak	Min  Peak	R1	wR2
无序处理前	1.8	-1.9	4.27%	11.19%
无序处理后	0.7	-0.8	3.20%	7.83%

视频演示操作请参阅：

单晶结构解析练习106(数据还原)：https://www.bilibili.com/video/BV1GJ4m187Un

参考文献

[1]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.

[2](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.

[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.

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