Closely related is mmCIF, macromolecular CIF, which is intended as an successor to the Protein Data Bank (PDB) format. It is now the default format used by the Protein Data Bank.
Also closely related is Crystallographic Information Framework, a broader system of exchange protocols based on data dictionaries and relational rules expressible in different machine-readable manifestations, including, but not restricted to, Crystallographic Information File and XML.