Dragon can process most of the common organic and inorganic molecules. However, some molecules can be rejected and this may depend either on a formally incorrect structure definition in the input file or on some restrictions fixed in Dragon.
If a molecule is rejected, the possible cause may be one of the following:
|▪||The molecule is a disconnected structure, e.g. two or more ions.|
|▪||The molecule includes hydrogens with more than one bond.|
|▪||The molecule includes a cyclic structure with too many circuits (i.e., fullerene derivatives, number of independent cycles more than 35 or the total number of circuits more than 4095).|
|▪||The molecule includes at least one atom with unusual valence due to missing hydrogens or erroneous bond type specification. |
|▪||The molecule includes at least one atom for which the quantity (number of valence electrons – number of bonded hydrogens – formal charge) = 0.|
|▪||If the molecule is entered as SMILES notation, unrecognized symbols have been used or some other SMILES rules have been followed.|