Large breathing effects in three-dimensional porous hybrid matter: facts, analyses, rules and consequences.

This critical review focuses on a strange behaviour of crystallized solid matter: its reversible swelling with large magnitude. This will be of interest for experts in porous solids but also for solid state chemists and physicists. Some examples, classified according to the dimensionality of the inorganic subnetwork, present the general requirements and the structural rules which govern the existence of this phenomenon. Its consequences concern specific applications related to sensors, energy savings, sustainable development and health (100 references).