​​The Cambridge Crystallographic Data Centre (CCDC).
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Retractions in the Cambridge Structural Database



Update: 1st November

In our last data release of 2023, scheduled for later this year, a further 152 entries implicated by the pre-print will be retracted. These retractions are already visible to users accessing the CSD via our web platforms and takes the total number of retractions related to the papermill pre-print in the CSD to 361.

We have updated the comments for 39 structures related to the papermill pre-print to say that following extensive review by the publishers and the CCDC there are currently no concerns on the data. A further 36 structures related to the papermill pre-print have been updated where our investigations have identified the entry has almost identical reflection data with another entry in the CSD with a different structural formula.  

Investigations are continuing for the remaining 556 structures implicated by the pre-print. Cases where reflection data has not yet been made available can be especially challenging to assess. We will continue to work with publishers, reviewers and depositors and are grateful for how the community has come together to tackle the issues so far.

Work to broaden the automated data integrity checks and processes, conversations with publishers on how we can support their peer review processes as well as collaborations with the community remain a key priority for the CCDC.

Update: 27th April

Our investigations continue on structures associated with a pre-print on papermills in crystallography. Previously, all structures were updated to contain an editorial comment that was visible in WebCSD. With this release this comment will now be visible on implicated structures in our desktop software.

Since being made aware of the pre-print, all implicated publishers have been contacted. We are aware of 125 publications that have been retracted as the result of investigations by the publishers. Therefore, 209 of the implicated structures have now been retracted from the CSD. The existing editorial comment on a further 39 structures has been updated to reflect where publishers have investigated and confirmed no issues have been identified (in agreement with CCDC integrity investigations).

We will continue to collaborate with publishers on the remaining structures following COPE guidelines and extend these new integrity checks out more widely in the CSD.

More about the data update here.


Update: 15th June 2022

In the latest CSD data update we have suspended the addition of 277 structures linked to publications implicated in the pre-print that had yet to be included in the desktop data release. Alongside these datasets we have also delayed the release of a number of other datasets related to those implicated in the pre-print, while our investigations continue.

In addition, we have removed all structures linked to publications mentioned in the papermill pre-print from our data subsets to minimize the impact of these structures.

More about the data update here.


Update: 5th May 2022

Our investigation following the recent pre-print on a prolific papermill in crystallography (https://doi.org/10.21203/rs.3.rs-1537438/v1) has found 992 structures linked to publications named there.

Of these, 715 are in the latest desktop release (2021.3  March 2022 CSD data update) and 277 are only available in our online versions of the CSD.

We have added a note to all impacted structures in the WebCSD which reads “This structure is currently under review following a 2022 study of a prolific papermill  https://doi.org/10.21203/rs.3.rs-1537438/v1.” For example:

A complete list of the specific refcodes affected is available on request, please email support@ccdc.cam.ac.uk.

We will continue to work with our contacts at the other databases and the journals involved to fully understand the issue, and will post significant updates here and on our Twitter @ccdc_cambridge.

Please contact support@ccdc.cam.ac.uk if you have any questions or concerns regarding this matter.


Update: 28th April 2022

Following the recent pre-print publication on Research Square (https://doi.org/10.21203/rs.3.rs-1537438/v1) we have begun investigations into potentially fraudulent data in the Cambridge Structural Database (CSD).

At the time of writing, we have so far identified 620 structures in the CSD which are associated to publications named in the pre-print. Our database team and data integrity scientist are working with our contacts at the other databases and the journals involved to fully understand the issue.

We take this matter very seriously. The CSD aims to be an accurate reflection of the literature, and so we will follow developments closely with the journals involved, and retract data when appropriate.

We are also working to add a note to all affected structures which will be visible on WebCSD once complete.

Our investigation to understand the issue and the root cause continues, internally and with our partners. We will post updates here as we learn more.

We acknowledge and appreciate the work the author of the pre-print has undertaken, as well as others that have taken efforts to alert us when issues like this arise.

Please contact support@ccdc.cam.ac.uk if you have any questions or concerns regarding this matter.




​You may have read with concern an Editorial Article by IUCr in Acta Crystallographica Section E: Structure Reports Online (2010), E66, e1-e2, which cited the publication of 70 structures based on falsified data. These originated from the groups of Dr Zhong and Professor Liu of Jinggangshan University, in 2007. The falsified data relating to these publications are, of course, included in the Cambridge Structure Database (CSD).

Structure data submitted for inclusion in the CSD have always gone through a rigorous process of curation. Our team of experienced editors checks depositions before they are passed into the database and we regularly contact depositors to clarify inconsistencies. This is a painstaking process in which we take great pride. We have always operated on a basis of trusting that the submitting scientist has acted honestly and, for the most part, our faith in the scientific community at large has not been dented by this unfortunate incident. Indeed, we congratulate the scientific team which uncovered the fraud and IUCr for their prompt, effective actions. We realise, however, that we must now be more vigilant for falsified data - a position we share with all publishing bodies that serve the crystallography community.

We are, first and foremost, scientists, so we cannot pretend this affair did not happen and simply airbrush the relevant entries in CSD out of existence. Such action would not serve our community well. We have therefore decided to flag each relevant entry as "Retracted", remove the data relating to it but to leave in place journal references and the DOI's of each retraction. CSD users will be contacted with procedures to update their installations accordingly.

Such instances of fraud are, thankfully, rare and we can now plan to take the steps necessary to detect others tempted to falsify data. This will ensure that the CSD remains the preeminent source of reliable, curated crystallography data, serving chemistry communities worldwide.