These assignments give the new mechanistic result that KHCO 3 -CD-MOF has a mixed carbonatebicarbonate chemisorption mechanism at an approximate 1 : 1.6 -1.9 ratio (at 0.8 -1.1 bar CO 2 ). This explains the ambiguous heats of adsorption data (Fig. ) which sees a chemisorptionphysisorption switch matching well to hydroxide saturation at a suggested 1 : 1.6 -2.4 ratio of carbonate : bicarbonate.