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Reaxys (English): Query Builder

Information about Reaxys, a web-based chemical database

What are the possibilities of the Query Builder



With the Query builder it is possible to combine all your keywords and different parameters together. In Quick Search you are limited to the combination of 2 factors (chemical structure and text). However in the Query builder it is possible to create a very well-structured and complex search strategy consisting of more than 2 factors.

Just like with Quick search you will be eventually directed to the Results page, here you can compare and analyze your results in an easy way. For extra help with your results, navigate to the tab Results.


  1. Click here to save your search query. This is only possible if registered and logged in
  2. Click here to search for results after completing your query
  3. You can drag subjects from these pictograms to easily enter chemical structures either by drawing, entering the molecular formula, entering the CAS-number or filling in a specific document number that reports that structure
  4. This menu shows all different entry options to build up your search query
  5. These operators can link your elements in different ways. To learn more about these operators, read the box: "Operators in Query Builder" on this page
  6. By clicking on this pictogram you can find all possible options for that specific entry, in this case all solvents. In this list you can also search and select multiple solvents to enter in your query.

Explanation Fields, Forms & History

In the Query builder you can select Fields, Forms and History in the top of the search-menu. 

Under the tab Fields you can find numerous different fields that can expand and specify your query. By clicking on one of these fields you add them to the query that is displayed in a box in the middle of the screen. Adding more boxes will make your query more specific. The boxes are linked via so-called operators. 

Under the tab Forms you can find standardized search forms for widely used search strategies, for example Spectra where a combination of NMR, MS and Chromatography data is requested. Search forms are ready-made combinations of existing "Fields".

Here you can find your most recent search. For non-registered users you can find all the search tasks you made during this session. Warning: if you are still busy on the computer but you are not using Reaxys, (you are for example working on a document or thesis while Reaxys is running in the background), Reaxys will automatically end your session after a extended time period. Your session can therefore expire without you actually closing the webpage. 
To prevent the loss of your previous searches, make sure to export or save your searches or make sure to register and log in. When you are logged in your searches will be saved for a longer period of time.

Operators in Query Builder


After building a search query by combining different elements you can further specify your query with the use of different operators. The standard operator used by Reaxys is the Boolean operator AND. This operator allows searching for documents where all the elements have to be included together. if you want another operator you can click on the operator to change it.

When entering multiple keywords in a single field, Reaxys automatically links these keywords with the PROXIMITY operator in order to increase the relevance of the found literature.

An overview of the different operators and there functions is displayed below. The relatively new operators NEAR and NEXT are explained below that.

NEAR: requires the search terms to be maximal 3 words away from each other (in any direction).

NEXT: requires the search terms to be maximal 3 words away from each other and to occur in the same order as they have occurred in the search query.

Both operators can only be used in the same field.