Metal-organic frameworks (MOFs) are crystalline porous solids formed by the combination of a metal and an organic linker, and the void space within the pores have made them highly interesting for applications such as gas storage and catalysis. Furthermore the pores are tuneable because substitution of structually similar ligands often results in a topologically identical crystal, which can however have different pore sizes, or differ in macroscopic properties such as light adsorption or response to pressure. Being mechanically softer than typical dense inorganic materials, MOFs are prone to structural disorder. This can be static in nature, e.g. arising from structural units occupying one of several equivalent sites with random ordering throughout the crystal, or dynamic, e.g. arising from the thermally activated switching of units between energetically similar sites.