Fig 17 . The six formal representation types for small molecules. Four of these, IUPAC names, SMILES, molefile or SD files and InChI strings are generally automatically interconvertible (but not the InChIKey). Note that a manual drawing tools (also termed sketchers) and rendering algorithms are related since they can both take as input (and usually also generate as output) either of the four interconvertible representations and subsequently convert these into screen renderings and/or PDF images of the structures (adapted from PMID: 30087946)