void OEMDLPerceiveParity(OEMolBase &mol)

This function sets the MDL stereo parity information for each atom from the OEChem TK stereochemistry. Any atom that has tetrahedral stereo specified has the corresponding MDL stereo parity value, one or two, placed in its ‘MDLParity’ generic data, with type unsigned int. This MDL stereo parity is relative to the current order of atoms returned by an iterator of atoms across a molecule. All other atoms, non-chiral or without stereo specified, have their MDL stereo parity set to zero or three.

OEMDLPerceiveParity internally calls the OEPerceiveChiral function, so there’s no need to explicitly call OEPerceiveChiral on a molecule prior to calling OEMDLPerceiveParity.


This function is the opposite of the OEMDLStereoFromParity function.


This function assumes that atoms have stereo parity values assigned explicitly. This is generally automatic when reading structure file formats, or via generation of conformers. For 3D structures from other sources, an explicit call to the OE3DToInternalStereo function prior to calling this function may be required to ensure atom stereo parities are assigned based on the 3D coordinates.

See also