When depositing a structure at the CCDC using the online deposition process, a search will be run on your structures to compare the unit cell dimensions with all the published structures in the Cambridge Structural Database (CSD) and the Inorganic Crystal Structure Database (ICSD).
The Reduced Cell Check runs on the validation stage of the deposit process and will compare the reduced cells of the data you are depositing to the reduced cells of all the published structures in the CSD. A reduced cell search will allow matching structures to be found irrespective of the space group setting used in each case. If any hits are found (using our default tolerances) a button to 'View Hits' will be visible. Clicking on the button will allow you to view the possible hits in our free Access Structures service.
If your data matches a structure that has already been published, you are still able to deposit your structure and this can still be published through the CSD. When you decide to publish a structure that is a redetermination of an existing structure, the structure will be added to the same refcode family as the existing structure. This allows the structures to be linked, which enables users to easily find the different determinations. Additional datasets of previously published structures can provide valuable information to researchers, and the CCDC actively encourages the deposition of all crystal data.