> For the complete documentation index, see [llms.txt](https://docs.materialsproject.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.materialsproject.org/apps/explorer-apps/mof-explorer/structure-details/qmof-ids.md).

# 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.