Because of their high surface areas,crystallinity, and tunableproperties, metal–organic frameworks (MOFs) have attractedintense interest as next-generation materials for gas capture andstorage. While much effort has been devoted to the discovery of newMOFs, a vast catalog of existing MOFs resides within the CambridgeStructural Database (CSD), many of whose gas uptake properties havenot been assessed. Here we employ data mining and automated structureanalysis to identify, “cleanup,” and rapidly predictthe hydrogen storage properties of these compounds. Approximately20 000 candidate compounds were generated from the CSD usingan algorithm that removes solvent/guest molecules. These compoundswere then characterized with respect to their surface area and porosity.Employing the empirical relationship between excess H2uptakeand surface area, we predict the theoretical total hydrogen storagecapacity for the subset of ∼4000 compounds exhibiting nontrivialinternal porosity. Our screening identifies several overlooked compoundshaving high theoretical capacities; these compounds are suggestedas targets of opportunity for additional experimental characterization.More importantly, screening reveals that the relationship betweengravimetric and volumetric H2density is concave downward,with maximal volumetric performance occurring for surface areas of3100–4800 m2/g. We conclude that H2storagein MOFs will not benefit from further improvements in surface areaalone. Rather, discovery efforts should aim to achieve moderate massdensities and surface areas simultaneously, while ensuring frameworkstability upon solvent removal. [ABSTRACT FROM AUTHOR]