Background

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The Cambridge Structural Database (CSD) is a primary source of experimental information on molecular geometries. For crystallographers and structural chemists, the main interest is often in bond lengths and angles. Comparison of the dimensions of a newly determined small-molecule crystal structure with the bond lengths and angles of similar structures in the CSD is useful as a check against refinement errors and to highlight unusual geometrical features.

•	Indeed, CSD-based printed compilations of the means, medians, and standard deviations of organic and organometallic bond lengths have been widely used to set up dictionaries for the restrained refinement of new crystal structures.

•	Mogul is a library of molecular geometry derived from the Cambridge Structural Database (CSD) and provides rapid access to the preferred values of bond lengths, valence angles and acyclic torsion angles.

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Mogul is primarily used for structure validation, e.g. checking the molecular dimensions of new crystal structures, or validating the conformations of calculated, or modelled molecules. However, Mogul can also be used to very quickly look up the value of e.g. a particular bond length in a given query molecule.