The archival community is presently addressing questions of semantic interoperability, which have been raised by linked open data and the Semantic Web. Current discussions on revisions to encoded archival description (EAD), for instance, are moving from document-based to more database-like element sets to facilitate greater interoperability. But to realise fully the potential benefits offered by such developments, further steps are needed. This article outlines a new experimental schema, which allows collection descriptions to be encoded in a more interoperable manner. Devised for the Collaborative European Digital Archive Architecture Project, it complements the descriptive elements of a collection-level record with more semantically precise metadata components. The schema was devised to form the core of a 'digital ecosystem', a rapidly changing research environment of which archival descriptions form a core part. The advantages of semantic interoperability and the data requirements to achieve it are discussed before a detailed description of the schema itself. The article then suggests some initial ways in which it could be employed to enhance access to collection descriptions, its compatibility with the Semantic Web and standards such as ISAD(G), and how it may be used in conjunction with EAD. The schema has yet to be evaluated in detail in working environments, and so is offered as a heuristic proof-of-concept for community discussion.