Navigation auf


Department of Chemistry

Searching the Cambridge Structural Database

The information provided here is intended primarily for members of the Department of Chemistry.

For assistance and questions, please contact
Prof. Bernhard Spingler
Office: 38 G 12
Tel: 54656
E-Mail: Bernhard Spingler


On-line documentation for searching the CSD

CSD Homepage

Go to X-ray User Info


How to access the Cambridge Structural Database (CSD) and start a basic search:

Software for accessing the CSD


The University of Zurich has a site license for the CSD and its related software. The best solution, offering the user the greatest flexibility, is to install the entire CSD System, which includes the software and database, on your own computer (Mac, Windows and Linux are supported). However, the CSD System cannot be downloaded directly by users. Please contact Prof. Spingler (contact details above) and he will make the relevant installers available to you and provide the license key. Installation can require about 20 GB of storage.

Once installed, the software and database update automatically three or four times during the year. At the end of each year, the entire next version of the CSD System must be obtained and installed.

WebCSD is an online alternative to the CSD search software ConQuest, but has less functionality. It is ideal for relatively straightforward searches. You can access WebCSD from anywhere in the UZH network, including via a VPN connection.

Mercury is a the structure visualisation and analysis program, which has a license-free standalone version that can be installed in the absence of the CSD System. The free version has some functionality disabled, but these functions can be activated by applying the license key obtainable from Prof. Spingler(contact details above).



The ConQuest graphical interface is quite intuitive. If you try the various options, you should quickly learn how to construct queries, perform searches and analyse the results. Interactive help and tutorials are available and the on-line manuals should be consulted for detailed information.

The structure drawing tool is similar to that of ChemDraw, but one key difference is that H-atoms are not implied. If you do not define H-atoms for a particular parent atom, structures with all possible substitutions at that site will be found. This is advantageous when looking for structures with a similar fragment or backbone, but might give too many hits when looking for a single specific compound.

Detailed on-line documentation is available. Help is also available during a search, as each window has a HELP menu or button.

If the manuals do not resolve a question, Prof. Spingler is available to assist you. He can also help with any questions that you might have about search strategies.

When using a local installation of the database, double-click on the ConQuest icon to start the software.

Some information will be displayed in a small window and then the main window will apppear. From the list of buttons on the left side select the Draw option to sketch a molecule and a new window will be displayed, while the other options allow you to enter various text or numerical information to search on.

In the Draw window, the ADD-3D option can be used to define geometrical tests for the search, so that these features can be analysed, or used later in the structure analysis program Vista. When drawing a fragment, remember that H-atoms are not implicit and you must define them to complete an atom's valency if you do not wish to find all structures with ANY substituent at the incomplete site(s).

Several questions can be built up before starting the search. Search questions do not have to be based solely on structural fragments. Text and numeric strings, such as authors' names, compound names, formula and year are a few examples of possible options. If you wish to develop multiple queries, choose the Store option after creating each individual query (choosing the Search option will start a search directly using the current query only). Multiple questions can be combined using the Combine Queries tab in the main window, e.g. with AND, OR, NOT, etc. You may also specify various options, such as to display only error-free data, or only structures for which atomic coordinates are available, or only organic structures, etc.

Further information is available in the comprehensive on-line documentation.


The search results

During a search with ConQuest, hits will be displayed in a list and you can select any hit and examine it in more detail while the rest of the search is running. Many options are available, including on-screen rotations of a 3D view of the structure and the ability to find bond lengths, angles and torsion angles just by clicking on the relevant atoms. Right-click in the 3D window to activate a menu. To reject any hit, click on the green tick in the list. A question that is too general could give a very large number of hits and the question may need to be defined more restrictively.

Search results will not be saved unless this is specifically requested (you will be warned if you attempt to exit without saving anything). Under the File-menu, a summary PDF file of the search results can be saved. If you want to work further with the atomic coordinates, use the "Export Entries As..." option of the File menu in ConQuest and the primary crystallographic data and atomic coordinates can be exported in CIF or several other formats.


Geometrical analysis of the search results

The program Mercury can be used to analyse the structures you saved during the search, provided some geometrical tests (e.g. bond lengths, angles, torsion angles, etc.) were defined with the ADD-3D button in the DRAW window of ConQuest during the building of the search question. Start Mercury from within ConQuest under the File-menu: "View in Mercury".

It is then possible to get a graphical analysis for various geometrical features, or to graphically look at the information available individually for each entry in the same way that the hits could be viewed during the original search. Thus it is possible to view the molecule in 3D and to rotate it on the screen, as well as look at individual bonding parameters. The full bibliographic data can also be viewed on the 1D screen.


The program Mercury can be used to view, rotate, draw and analyse the structures you saved during the search. This is similar to the 3D viewer available during the search itself, but may be faster when used locally. Mercury for the Mac or Windows PC can be downloaded freely from the CCDC web site. We have a site license to activate some additional features in Mercury. If you want full functionality, please ask Prof. Spingler for the license key (contact details above).


Searches on the Inorganic Crystal Structure Database (ICSD)

The structural details of inorganic compounds (i.e. compounds not containing at least one carbon atom) are not stored in the Cambridge Structural Database, but in a separate database known as the Inorganic Crystal Structure Database. The ICSD can be searched with a web browser from anywhere in the UZH network, including via a VPN connection.


Searches on the Protein Databank (PDB)

The structural details of proteins larger than 24 residues are not stored in the Cambridge Structural Database, but in a separate database known as the Protein Databank. The PDB can be searched with a web browser.


Searches on the Nucleic Acids Database (NDB)

The structural details of nucleic acids larger than trinucleotides are not stored in the Cambridge Structural Database, but in a separate database known as the Nucleic Acid Database. The NDB contains structures of oligonucleotides and nucleic acids and can be searched with a web browser. This site also has links to databases containing the structural details of DNA-binding proteins and the structures of nucleic acids determined by NMR.