
Adding chemical compounds to Wikidata is not difficult. You can store the chemical formula (P274), (canonical) SMILES (P233), InChIKey (P235) (and InChI (P234), of course), as well various database identifiers (see what I wrote about that [here(http://chem-bla-ics.blogspot.nl/2015/12/new-edition-getting-cas-registry.html)]). It also allows storing of the provenance, and has predicates for that too.