termed an "empty channel" mechanism, which is also demonstrated in purely inorganic frameworks such as tuperssuatsiaite. 19 As a third example, we can cite the recent investigation into the mechanism of abnormal in-plane stretchability of 2D MOF NiF 2 (pyrazine) 2 . Fan et al. used MD simulations based on a machine learning potential (MLP) in order to probe in silico the highly anisotropic behavior of this material, showing that uniaxial tensile strain resulted in a decrease of its in-plane area -a mechanism that could make the MOF appealing for applications in thin films. Finally, Vervoorts et al. identified the important role of linker side chains in the pressure response of the Cu 2 (DB-bdc) 2 dabco MOF. 20 They demonstrated, through high-pressure powder X-ray diffraction and molecular dynamics simulations, that linker configurational entropy can be a determining factor in the thermodynamics of flexible MOFs, and opened the way to further tuning of MOF mechanical behavior through ligand functionalization.