Interoperable sample metadata: Interoperable metadata are needed in particular to compare the materials with other available materials and to query additional databases. The sample metadata in the Chemotion repository include standardized molecule descriptors following domain-specific standards such as InChI, InChI keys and canonical SMILES strings wherever applicable. The terminologies used in the description of the samples are chosen from domain relevant ontologies and are assigned to the identifiers of the mentioned ontologies.