Several structures are fully occupied with xenon even at room temperature and pressure, suggesting they may form quite easily. We have also found structures that adsorb CO 2 , for instance mF180_R-R_18, see This structure, which has an unusually large CO 2 heat of desorption, q = -52.8 kJ/mol, adsorbs large quantities of CO 2 even below 1 bar of CO 2 pressure and above room temperature. The cavity to guest volume ratio for this structure is ideal, 57%.