How Reliable Are Intermolecular Interaction Energies Estimated from Topological Analysis of Experimental Electron Densities?

We examine the reliability of intermolecular interaction energies estimated from intermolecular bond critical point properties of experimental electron densities and show that they are inherently unreliable, typically underestimating but sometimes overestimating more reliable values. Based on these estimates, conclusions regarding the energetic importance of specific intermolecular interactions, especially in the context of crystal packing and crystal engineering, can be misleading.