Molecule and reaction valence bond representation. Read and write file formats: SMILES, SDF, InChI, Mol2, CML, and others. Efficient molecule processing algorithms: Ring Finding, Kekulisation, Aromaticity. Coordinate generation and rendering. Canonical identifiers for fast exact searching. Substructure and SMARTS pattern searching. ECFP, Daylight, MACCS, and other fingerprint methods for similarity searching. QSAR descriptor calculations