InChI is the International Chemical Identifier developed by the International Union of Pure and Applied Chemistry (IUPAC) in collaboration with the U.S. National Institute of Standards and Technology (NIST) and the InChI Trust . The InChI establishes a unique label for each chemical compound, facilitating the linking of diverse data compilations. This linear notation system resolves the inconvenient and chemical ambiguities of the SMILES language about stereocenter, tautomer, and valence .