Though one could search for a property document using defining characteristics such as molecule ID, for convenience, we also define IDs for property documents. These IDs are generated by constructing a string with the identifying information for the document (including MPculeID, solvent, and -where relevant -method, as well as potentially other information used to generate the document); this string is then hashed using the BLAKE2 algorithm, as implemented in the Python standard library. The uniqueness of a hash can in general not be guaranteed, but because there are other ways to access a desired property document using data that are essentially guaranteed to be unique, the relatively remote possibility of hash collisions is acceptable in the case of property documents.