好象那是CSD refcode, 六个字母组成.

CCDC # 则是你deposit 数据后给的一个六位数, 早期的结构好象没有.

另外, 无机数据库的也叫CSD # 或ICSD #

FIZ Karlsruhe prefers the electronic submission of crystal structure data. After each initial deposition we will provide you with a CSD number for later reference.
Example of a typical reference:
"Further details of the crystal structure investigation(s) may be obtained from Fachinformationszentrum Karlsruhe, 76344 Eggenstein-Leopoldshafen, Germany (fax: (+49)7247-808-666; e-mail: crysdata(at)fiz-karlsruhe.de, http://www.fiz-karlsruhe.de/request_for_deposited_data.html) on quoting the appropriate CSD number"
Authors are asked to submit changes to the deposited data directly to FIZ Karlsruhe  The corrected files will be stored in our depot with the same CSD number.  Please send corrections per e-mail, the "subject" field of your e-mail should read "corrected version of CSD-nnnnnn".


http://www.fiz-karlsruhe.de/depositing_crystal_structures.html

CCDC和CSD貌似是两个不同的数据库

简而言之，CSD是CCDC公司下的一款商品。CCDC的全称是：Cambridge Crystallographic Data Centre， 而CSD的全称是：Cambridge Structural Database。
可以说CSD 号是从CCDC号转化提取，并不断更新增加过来的：
1，结构被deposite到CCDC，就像是一个结构被建立了档案，每个档案的索引号就是所谓的ccdc号了。
2，而当结构发表之后，该结构的CCDC号也就被加入到CSD系统中，并赋予一个新的索引号（RefID)。也就是所谓的CSD号了。

所以，请注意CCDC索引号和CSD索引号完全不是同一会事情。无论从形式上还是功能上都不是不同的。
下面给CCDC网站原文介绍：
The Cambridge Crystallographic Data Centre accepts depositions of crystal structure data from X-ray and neutron diffraction studies, and from powder studies using a constrained refinement, forrganic compounds /metal-organic compounds.These data should be sent to deposit@ccdc.cam.ac.uk following the instructions below:

Data depositions with the CCDC are of two main types:

Pre-Publication: your structure(s) are being submitted for publication in a journal
Private Communications to the CSD: your structure(s) are not intended for publication, but you wish them to be available to other scientists through the CSD

However, data for structures which have already appeared in a journal and are not yet in the CSD are always welcome. Depositions should include the list of authors and the full journal reference. An electronic or printed copy of the journal article is appreciated, especially for the less-common journals.

Note that data for Acta Crystallographica and Zeitschrift für Kristallographie - New Crystal Structures are received from the Editorial offices.

The electronic CIF format should be used for all depositions. If this causes significant problems, please contact deposit@ccdc.cam.ac.uk to discuss other possible formats. However, most major journals now require cifs and the notes for authors should be consulted.

On receipt, all depositions are stored in the secure and separate CCDC Supplementary Data Archive. After publication, deposited structures will be processed to the main distributed CSD, and the original deposited data will also be made freely available to all scientists on request, for bona fide research purposes，

从楼上各位学习了！