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Topicity In stereochemistry, topicity is the stereochemical relationship between substituents and the structure to which they are attached. Depending on the relationship, such groups can be ''heterotopic'', ''homotopic'', ''enantiotopic'', or ''diastereotopic''. ==Homotopic== Homotopic groups in a chemical compound are equivalent groups. Two groups A and B are homotopic if the molecule remains the same (including stereochemically) when the groups are interchanged with the remaining parts of the molecule fixed. Homotopic atoms are always identical, in any environment. Homotopic NMR-active nuclei have the same chemical shift in an NMR spectrum. For example, the four hydrogen atoms of methane (CH4) are homotopic with one another, as are the two hydrogens or the two chlorines in dichloromethane (CH2Cl2).
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Topicity」の詳細全文を読む
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