On the Thermodynamics of Framework Breathing: A Free Energy Model for Gas Adsorption in MIL-53

When adsorbing guest molecules, the porous metal–organic framework MIL-53(Cr) may vary its cell parameters drastically while retaining its crystallinity. A first approach to the thermodynamic analysis of this “framework breathing” consists of comparing the osmotic potential in two distinct shapes only (large-pore and narrow-pore). In this paper, we propose a generic parametrized free energy model including three contributions: host free energy,...