cookie preferences

The table below lists the cookies used on and associated websites, and gives a brief description of their purpose. More details of the IUCr's privacy policy are available here.

Essential cookies

Always active

These cookies are necessary for our websites to function and cannot be switched off in our systems. A number of essential cookies are set by the IUCr:

iucrchublogin, session_id, SQ_system_session, publbio_phpsessid

These are essential 'session cookies' used when a visitor signs-in to IUCr online services such as the World Directory of Crystallographers, or publication tools such as publBio, or when a visitor is requesting or paying for vouchers and open-access fees etc. Session cookies ensure that the server sends the appropriate data securely to the browser that is hosting the session, and that any data transactions during that session are associated with that particular visitor. When the session is terminated (e.g. the visitor signs-out, completes the transaction, or closes the browser), the session cookie is destroyed.

iucr_ref_lookup_yellow, iucr_ref_lookup_orange, iucr_residue_annotation

These cookies store a visitor's preferences for displaying content, e.g. links to the Online Dictionary of Crystallography, the IUPAC Gold Book, and interactive biological annotations. These are persistent cookies, set by user interaction.


This cookie records a visitor's preferences regarding non-essential third-party content (see Third-party cookies below). It is a persistent cookie, set by user interaction.

Our articles also have associated metadata maintained by our publishing partners, who use cookies as part of their service:


Crossref uses cookies to give Crossmark access to the current status of journal articles, i.e. whether they have been updated, corrected or retracted, as well as providing access to additional article metadata. To learn more about Crossref's privacy policy, see


Cookies are set by Kudos ( as part of its service to help journal authors maximize the impact of their publications.

Third-party cookies

The IUCr websites include third-party applications to provide additional functionality to readers, and to allow us to improve our service using anonymous analytics data. The third parties mentioned below set cookies. This content is optional, but certain features of our websites will not work when these cookies are switched off.


The IUCr Facebook page is embedded in a small number of IUCr web pages. To learn more about Facebook's privacy policy, see

Google Analytics

Google Analytics cookies are used to collect information about how visitors use our websites. We use the information to help us improve our sites. The cookies collect information in an anonymous form, including the number of visitors, where visitors have come to the site from and the pages they visited. To learn more about Google Analytics' privacy policy, see


TrendMD ( cookies allow article recommendations from scholarly websites to be included in our journal articles.


Twitter feeds are included in a number of IUCr web pages to provide extra news and information to readers. To learn more about Twitter's privacy policy, see


YouTube cookies are used in pages with embedded video content. To learn more about YouTube's privacy policy, see

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