The components interact via non-covalent interactions such as hydrogen bonding, ionic interactions, van der Waals interactions and Π-interactions. These interactions lead to a cocrystal lattice energy that is generally more stable than the crystal structures of the individual components. The intermolecular interactions and resulting crystal structures can generate physical and chemical properties that differ from the properties of the individual components. Such properties include melting point, solubility, chemical stability, and mechanical properties. Some cocrystals have been observed to exist as polymorphs, which may display different physical properties depending on the form of the crystal.
Phase diagrams determined from the "contact method" of thermal microscopy is valuable in the detection of cocrystals. The construction of these phase diagrams is made possible due to the change in melting point upon cocrystallization. Two crystalline substances are deposited on either side of a microscope slide and are sequentially melted and resolidified. This process creates thin films of each substance with a contact zone in the middle. A melting point phase diagram may be constructed by slow heating of the slide under a microscope and observation of the melting points of the various portions of the slide. For a simple binary phase diagram, if one eutectic point is observed then the substances do not form a cocrystal. If two eutectic points are observed, then the composition between these two points corresponds to the cocrystal.