MOF descriptors that are commonly used are geometrical descriptors that describe their pore environment such as pore diameter, void fraction, framework density, volumetric and gravimetric surface area. There are also chemical descriptors to account for the different chemical environments, in a simple form they are based on atom or building block density present in the structure, or a more sophisticated descriptor is based on radial distribution functions weighted by an atomic property, such as electronegativity, polarizability and van der Waals volume for predicting gas uptake capacities. Topological descriptors account for bonding information and connectivity of atoms within a material. Some recent efforts have employed Pair Distribution Functions, PDFs, to describe MOF structure, especially where defects alter the structure. To develop our descriptor, we consider the fact that host-guest interactions occur mainly by the influence of local interaction, thereby only including a small effect from the linkers in adjacent pores. In addition, while there are 2941 3D topologies (nets) reported in the RSCR database to date, they consist of repeating a limited number of pore shapes, such as cubic, tetrahedral, octahedral, square antiprism and cuboctahedral. These two considerations combined, brings us to observe and isolate the potential created by each functionalized pore shape. To describe the distribution of chemically important functional groups, we consider only the key atoms of each functional group (e.g. the N atom of the NH 2 group) and neglect the rest of the framework, effectively resulting in a simplified PDF representing the distances between pairs of functional groups in each MOF pore.