An unusual case of OD-allotwinning: 9,9′-(2,5-dibromo-1,4-phenylene)bis[9H-carbazole]

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• 作者：Paul Kautny ; Thomas Schwartz ; Berthold Stö ; ger and Johannes Frö ; hlich
• 关键词：twinning ; allotwinning ; order&ndash ; disorder polytypism
• 刊名：Acta Crystallographica Section B
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：73
• 期：1
• 页码：65-73
• 全文大小：1035K
• ISSN：2052-5206

文摘

9,9′-(2,5-Dibromo-1,4-phenylene)bis[9H-carbazole] (1) crystallizes as a category I order–disorder (OD) structure composed of non-polar layers of one kind with B2/m(1)1 layer symmetry. The crystals are made up of the two polytypes with a maximum degree of order (MDO). The monoclinic MDO₁ polytype (B2₁/d) possesses an orthorhombic B-centered lattice and appears in two orientations, which are related by reflection at (100). The orthorhombic MDO₂ polytype (F2dd) has a doubled b-axis and appears in two orientations, which are related by inversion. The crystal structures of both polytypes were determined in a concurrent refinement. The MDO₁:MDO₂ ratio is 69:31.