well as an ensemble-average heat of adsorption. We expected to find dependencies between these quantities and the size of the cavities. Naïvely, one would expect that small pores are enthalpically favoured, while larger pores allow the guests to move more freely, contributing additional entropy. Surprisingly, we found that apparently (meta-)stable structures that are able to adsorb quantitatively can have a very wide range of packing coefficients, and that there are no apparent correlations between cavity size and thermodynamics. Perhaps needless to say, we encourage the scientific community to try to isolate the predicted clathrates.