On the other hand, the InChIKey is a condensed/hashed form of the full InChI string. These 27 characters alphabetic keys are particularly useful for rapid searching and indexing in chemical databases. The sum formula of a molecule, connectivity, hydrogen positions, and charge of the basic molecular skeleton are encoded within the first 14 characters. These are followed by a hyphen and another string which consists of 10 characters: the first eight which encode the features that supplement the core data (metal ligation, stereochemistry, tautomerism, and isotopic substitution), and the remaining two which indicate whether the initial InChI was a Standard InChI or not, as well as the InChI software version number. The (de)protonation state is indicated by the final character of the InChIKey. The InChIKey serves as a global identifier, facilitating seamless integration and interoperability across diverse chemical databases and applications.