Chinese term (edited): 4���ȴ����

I could see the position of the structure, but couldn't retrieve it.

3-氯代苯酐或4-氯代苯酐都是苯酐的衍生物。苯酐(Phthalic anhydride)，通常是指邻苯二甲酸酐，即邻苯二甲酸的两个酸根脱去一分子水而形成邻苯二甲酸酐。也就是说，苯环的1、2位上连着两个羰基，而这两个羰基又共同与一个氧原子相连。如果苯环的第3位或第4位上的那个氢被氯取代，就分别形成了3-氯代苯酐或4-氯代苯酐。如果该网站的结构式与我描述的一样，那么该名称就是对的。苯酐有很多同义词，如：Phthalic acid anhydride、1,2-Benzenedicarboxylic acid anhydride、1,2-benzenedicarboxylic anhydride等，所以相应地氯代苯酐也会有很多同义词。


If the structure on that webpage is not the same as I described, please download it and send it to me by email, I will figure it out.

那么也许你要问，有没有5-氯代苯酐或6-氯代苯酐？答案是NO，因为如果你从另一方向来数，5-氯代苯酐就是4-氯代苯酐。有机化学命名的原则是，当取代基的位号有几种可能时则尽量取小的。同理，6-氯代苯酐就是3-氯代苯酐。

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Note added at 2 days 12 hrs 37 mins (2004-04-14 13:41:28 GMT) Post-grading
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Jianming,

I did see the instruction (图片点击放大), but every time when I clicked on the link, I got the message “The page cannot be displayed”. It may be easier for you to retrieve the picture from China. Anyway, it doesn\'t matter. I agreed with Mr. Liu two days ago. I didn\'t intend to get the points when I posted my answer. I said many times that Kudoz points were not my motive. Thank you!