# QMOF IDs Each material in the QMOF Database is assigned a unique 7-digit QMOF ID that is associated with that material. All calculations associated with a given QMOF ID are for a given PBE-D3(BJ) optimized structure. Each QMOF ID represents a unique structure, as determined using Pymatgen's [StructureMatcher](https://pymatgen.org/pymatgen.analysis.structure_matcher.html#pymatgen.analysis.structure_matcher.StructureMatcher). As such, the primitive unit cells of any two structures are distinct after any relevant volume rescaling. Depending on your personal definition of a unique material, you may wish to further unique-ify the structures. For instance, MOFs with closed-pore and open-pore configurations would be considered unique, MOFs with different linker configurations would be considered unique, and so on. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.materialsproject.org/apps/explorer-apps/mof-explorer/structure-details/qmof-ids.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.